diff --git a/icu4c/source/data/brkitr/rules/line.txt b/icu4c/source/data/brkitr/rules/line.txt
index de9bc8e33a54..538e3865f3e0 100644
--- a/icu4c/source/data/brkitr/rules/line.txt
+++ b/icu4c/source/data/brkitr/rules/line.txt
@@ -23,21 +23,11 @@
 !!chain;
 !!quoted_literals_only;
 
-# Prototype definitions for L2/22-080R
-# Line breaking at orthographic syllable boundaries
-
-$AK = [\u1B05-\u1B33 \u1B45-\u1B4C \u25CC \uA984-\uA9B2 \U00011005-\U00011037 \U00011071-\U00011072 \U00011075 \U00011305-\U0001130C \U0001130F-\U00011310 \U00011313-\U00011328 \U0001132A-\U00011330 \U00011332-\U00011333 \U00011335-\U00011339 \U00011360-\U00011361 \U00011392-\U000113B5 \U00011F04-\U00011F10 \U00011F12-\U00011F33];
-
-$AP = [\U00011003-\U00011004 \U000113D1 \U00011F02];
-
-$AS = [\u1BC0-\u1BE5 \uAA00-\uAA28 \U00011066-\U0001106F \U00011350 \U0001135E-\U0001135F \U00011380-\U00011389 \U0001138B \U0001138E \U00011390-\U00011391 \U00011EE0-\U00011EF1 \U00011F50-\U00011F59];
-
-$VF = [\u1BF2-\u1BF3];
-
-$VI = [\u1B44 \uA9C0 \U00011046 \U0001134D \U000113D0 \U00011F42];
-
 $AI = [:LineBreak =  Ambiguous:];
+$AK = [:LineBreak =  Aksara:];
 $AL = [:LineBreak =  Alphabetic:];
+$AP = [:LineBreak =  Aksara_Prebase:];
+$AS = [:LineBreak =  Aksara_Start:];
 $BA = [:LineBreak =  Break_After:];
 $HH = [\u2010];     # \u2010 is HYPHEN, default line break is BA.
 $BB = [:LineBreak =  Break_Before:];
@@ -77,6 +67,8 @@ $SA = [:LineBreak =  Complex_Context:];
 $SG = [:LineBreak =  Surrogate:];
 $SP = [:LineBreak =  Space:];
 $SY = [:LineBreak =  Break_Symbols:];
+$VF = [:LineBreak =  Virama_Final:];
+$VI = [:LineBreak =  Virama:];
 $WJ = [:LineBreak =  Word_Joiner:];
 $XX = [:LineBreak =  Unknown:];
 $ZW = [:LineBreak =  ZWSpace:];
@@ -95,7 +87,7 @@ $ExtPictUnassigned = [\p{Extended_Pictographic} & \p{Cn}];
 #         list it in the numerous rules that use CM.
 # By LB1, SA characters with general categor of Mn or Mc also resolve to CM.
 
-$CM = [[[:LineBreak = Combining_Mark:] $ZWJ [$SA & [[:Mn:][:Mc:]]]] - [$VF $VI]];
+$CM = [[:LineBreak = Combining_Mark:] $ZWJ [$SA & [[:Mn:][:Mc:]]]];
 $CMX = [[$CM] - [$ZWJ]];
 
 #   Dictionary character set, for triggering language-based break engines. Currently
@@ -110,7 +102,7 @@ $dictionary = [$SA];
 #                               XX  (Unknown, unassigned)
 #                         as $AL  (Alphabetic)
 #
-$ALPlus = [[$AL $AI $SG $XX [$SA-[[:Mn:][:Mc:]]]] - [$AS $AK $AP]];
+$ALPlus = [$AL $AI $SG $XX [$SA-[[:Mn:][:Mc:]]]];
 
 
 ## -------------------------------------------------
@@ -228,7 +220,27 @@ $OP $CM* $SP+ $CM+ $AL_FOLLOW?;    # by rule 10, stand-alone CM behaves as AL
                                    # by rule 8, CM following a SP is stand-alone.
 
 
-# LB 14a Force a break before start of a number with a leading decimal pt, e.g. " .23"
+# LB 15a
+($OP $CM* $SP+ | [$OP $QU $GL] $CM*) ([\p{Pi} & $QU] $CM* $SP*)+ .;
+($OP $CM* $SP+ | [$OP $QU $GL] $CM*) ([\p{Pi} & $QU] $CM* $SP*)+ $SP $CM+ $AL_FOLLOW?;
+^([\p{Pi} & $QU] $CM* $SP*)+ .;
+^([\p{Pi} & $QU] $CM* $SP*)+ $SP $CM+ $AL_FOLLOW?;
+
+# LB 15b
+$LB8NonBreaks [\p{Pf} & $QU] $CM* [$SP $GL $WJ $CL $QU $CP $EX $IS $SY $BK $CR $LF $NL $ZW {eof}];
+$CAN_CM $CM*  [\p{Pf} & $QU] $CM* [$SP $GL $WJ $CL $QU $CP $EX $IS $SY $BK $CR $LF $NL $ZW {eof}];
+^$CM+  [\p{Pf} & $QU] $CM* [$SP $GL $WJ $CL $QU $CP $EX $IS $SY $BK $CR $LF $NL $ZW {eof}];
+
+# Messy interaction: manually chain between LB 15b and LB 15a on Pf Pi.
+$LB8NonBreaks [\p{Pf} & $QU] $CM* ([\p{Pi} & $QU] $CM* $SP*)+ .;
+$LB8NonBreaks [\p{Pf} & $QU] $CM* ([\p{Pi} & $QU] $CM* $SP*)+ $SP $CM+ $AL_FOLLOW?;
+$CAN_CM $CM*  [\p{Pf} & $QU] $CM* ([\p{Pi} & $QU] $CM* $SP*)+ .;
+$CAN_CM $CM*  [\p{Pf} & $QU] $CM* ([\p{Pi} & $QU] $CM* $SP*)+ $SP $CM+ $AL_FOLLOW?;
+^$CM+  [\p{Pf} & $QU] $CM* ([\p{Pi} & $QU] $CM* $SP*)+ .;
+^$CM+  [\p{Pf} & $QU] $CM* ([\p{Pi} & $QU] $CM* $SP*)+ $SP $CM+ $AL_FOLLOW?;
+
+
+# LB 15c Force a break before start of a number with a leading decimal pt, e.g. " .23"
 #        Note: would be simpler to express as "$SP / $IS $CM* $NU;", but ICU rules have limitations.
 #        See issue ICU-20303
 
@@ -238,7 +250,7 @@ $SP $IS           / [^ $CanFollowIS $NU $CM];
 $SP $IS $CM* $CMX / [^ $CanFollowIS $NU $CM];
 
 #
-# LB 14b Do not break before numeric separators (IS), even after spaces.
+# LB 15d Do not break before numeric separators (IS), even after spaces.
 
 [$LB8NonBreaks - $SP] $IS;
 $SP $IS $CM* [$CanFollowIS {eof}];
@@ -248,9 +260,6 @@ $CAN_CM $CM*  $IS;
 ^$CM+         $IS;              # by rule 10, stand-alone CM behaves as AL
 
 
-# LB 15
-$QU $CM* $SP* $OP;
-
 # LB 16
 ($CL | $CP) $CM* $SP* $NS;
 
@@ -351,8 +360,8 @@ $PR $CM* ($JL | $JV | $JT | $H2 | $H3);
 ($ALPlus | $HL) $CM* ($ALPlus | $HL);
 ^$CM+ ($ALPlus | $HL);      # The $CM+ is from rule 10, an unattached CM is treated as AL
 
-#LB 28b  Do not break Orthographic syllables
-($AP $CM*)? ($AS | $AK) ($CM* $VI $CM* $AK)* ($CM* $VI | (($CM* $AS | $CM* $AK)? $CM* $VF))?;
+#LB 28a  Do not break Orthographic syllables
+($AP $CM*)? ($AS | $AK | [◌] ) ($CM* $VI $CM* ($AK | [◌] ))* ($CM* $VI | (($CM* ($AS | $AK | [◌] ) )? $CM* $VF))?;
 
 # LB 29
 $IS $CM* ($ALPlus | $HL);
diff --git a/icu4c/source/data/brkitr/rules/line_cj.txt b/icu4c/source/data/brkitr/rules/line_cj.txt
index e3fabc29b4e8..b5ba6d629660 100644
--- a/icu4c/source/data/brkitr/rules/line_cj.txt
+++ b/icu4c/source/data/brkitr/rules/line_cj.txt
@@ -25,7 +25,10 @@
 !!quoted_literals_only;
 
 $AI = [:LineBreak =  Ambiguous:];
+$AK = [:LineBreak =  Aksara:];
 $AL = [:LineBreak =  Alphabetic:];
+$AP = [:LineBreak =  Aksara_Prebase:];
+$AS = [:LineBreak =  Aksara_Start:];
 $BA = [:LineBreak =  Break_After:];
 $HH = [\u2010];     # \u2010 is HYPHEN, default line break is BA.
 $BB = [:LineBreak =  Break_Before:];
@@ -65,6 +68,8 @@ $SA = [:LineBreak =  Complex_Context:];
 $SG = [:LineBreak =  Surrogate:];
 $SP = [:LineBreak =  Space:];
 $SY = [:LineBreak =  Break_Symbols:];
+$VF = [:LineBreak =  Virama_Final:];
+$VI = [:LineBreak =  Virama:];
 $WJ = [:LineBreak =  Word_Joiner:];
 $XX = [:LineBreak =  Unknown:];
 $ZW = [:LineBreak =  ZWSpace:];
@@ -216,7 +221,27 @@ $OP $CM* $SP+ $CM+ $AL_FOLLOW?;    # by rule 10, stand-alone CM behaves as AL
                                    # by rule 8, CM following a SP is stand-alone.
 
 
-# LB 14a Force a break before start of a number with a leading decimal pt, e.g. " .23"
+# LB 15a
+($OP $CM* $SP+ | [$OP $QU $GL] $CM*) ([\p{Pi} & $QU] $CM* $SP*)+ .;
+($OP $CM* $SP+ | [$OP $QU $GL] $CM*) ([\p{Pi} & $QU] $CM* $SP*)+ $SP $CM+ $AL_FOLLOW?;
+^([\p{Pi} & $QU] $CM* $SP*)+ .;
+^([\p{Pi} & $QU] $CM* $SP*)+ $SP $CM+ $AL_FOLLOW?;
+
+# LB 15b
+$LB8NonBreaks [\p{Pf} & $QU] $CM* [$SP $GL $WJ $CL $QU $CP $EX $IS $SY $BK $CR $LF $NL $ZW {eof}];
+$CAN_CM $CM*  [\p{Pf} & $QU] $CM* [$SP $GL $WJ $CL $QU $CP $EX $IS $SY $BK $CR $LF $NL $ZW {eof}];
+^$CM+  [\p{Pf} & $QU] $CM* [$SP $GL $WJ $CL $QU $CP $EX $IS $SY $BK $CR $LF $NL $ZW {eof}];
+
+# Messy interaction: manually chain between LB 15b and LB 15a on Pf Pi.
+$LB8NonBreaks [\p{Pf} & $QU] $CM* ([\p{Pi} & $QU] $CM* $SP*)+ .;
+$LB8NonBreaks [\p{Pf} & $QU] $CM* ([\p{Pi} & $QU] $CM* $SP*)+ $SP $CM+ $AL_FOLLOW?;
+$CAN_CM $CM*  [\p{Pf} & $QU] $CM* ([\p{Pi} & $QU] $CM* $SP*)+ .;
+$CAN_CM $CM*  [\p{Pf} & $QU] $CM* ([\p{Pi} & $QU] $CM* $SP*)+ $SP $CM+ $AL_FOLLOW?;
+^$CM+  [\p{Pf} & $QU] $CM* ([\p{Pi} & $QU] $CM* $SP*)+ .;
+^$CM+  [\p{Pf} & $QU] $CM* ([\p{Pi} & $QU] $CM* $SP*)+ $SP $CM+ $AL_FOLLOW?;
+
+
+# LB 15c Force a break before start of a number with a leading decimal pt, e.g. " .23"
 #        Note: would be simpler to express as "$SP / $IS $CM* $NU;", but ICU rules have limitations.
 #        See issue ICU-20303
 
@@ -226,7 +251,7 @@ $SP $IS           / [^ $CanFollowIS $NU $CM];
 $SP $IS $CM* $CMX / [^ $CanFollowIS $NU $CM];
 
 #
-# LB 14b Do not break before numeric separators (IS), even after spaces.
+# LB 15d Do not break before numeric separators (IS), even after spaces.
 
 [$LB8NonBreaks - $SP] $IS;
 $SP $IS $CM* [$CanFollowIS {eof}];
@@ -236,9 +261,6 @@ $CAN_CM $CM*  $IS;
 ^$CM+         $IS;              # by rule 10, stand-alone CM behaves as AL
 
 
-# LB 15
-$QU $CM* $SP* $OP;
-
 # LB 16
 ($CL | $CP) $CM* $SP* $NS;
 
@@ -339,6 +361,9 @@ $PR $CM* ($JL | $JV | $JT | $H2 | $H3);
 ($ALPlus | $HL) $CM* ($ALPlus | $HL);
 ^$CM+ ($ALPlus | $HL);      # The $CM+ is from rule 10, an unattached CM is treated as AL
 
+#LB 28a  Do not break Orthographic syllables
+($AP $CM*)? ($AS | $AK | [◌] ) ($CM* $VI $CM* ($AK | [◌] ))* ($CM* $VI | (($CM* ($AS | $AK | [◌] ) )? $CM* $VF))?;
+
 # LB 29
 $IS $CM* ($ALPlus | $HL);
 
diff --git a/icu4c/source/data/brkitr/rules/line_loose.txt b/icu4c/source/data/brkitr/rules/line_loose.txt
index ca76ecc9a2f3..37a8e0e84607 100644
--- a/icu4c/source/data/brkitr/rules/line_loose.txt
+++ b/icu4c/source/data/brkitr/rules/line_loose.txt
@@ -30,7 +30,10 @@
 !!quoted_literals_only;
 
 $AI = [:LineBreak =  Ambiguous:];
+$AK = [:LineBreak =  Aksara:];
 $AL = [:LineBreak =  Alphabetic:];
+$AP = [:LineBreak =  Aksara_Prebase:];
+$AS = [:LineBreak =  Aksara_Start:];
 $BA = [:LineBreak =  Break_After:];
 $HH = [\u2010];     # \u2010 is HYPHEN, default line break is BA.
 $BB = [:LineBreak =  Break_Before:];
@@ -71,6 +74,8 @@ $SA = [:LineBreak =  Complex_Context:];
 $SG = [:LineBreak =  Surrogate:];
 $SP = [:LineBreak =  Space:];
 $SY = [:LineBreak =  Break_Symbols:];
+$VF = [:LineBreak =  Virama_Final:];
+$VI = [:LineBreak =  Virama:];
 $WJ = [:LineBreak =  Word_Joiner:];
 $XX = [:LineBreak =  Unknown:];
 $ZW = [:LineBreak =  ZWSpace:];
@@ -222,7 +227,27 @@ $OP $CM* $SP+ $CM+ $AL_FOLLOW?;    # by rule 10, stand-alone CM behaves as AL
                                    # by rule 8, CM following a SP is stand-alone.
 
 
-# LB 14a Force a break before start of a number with a leading decimal pt, e.g. " .23"
+# LB 15a
+($OP $CM* $SP+ | [$OP $QU $GL] $CM*) ([\p{Pi} & $QU] $CM* $SP*)+ .;
+($OP $CM* $SP+ | [$OP $QU $GL] $CM*) ([\p{Pi} & $QU] $CM* $SP*)+ $SP $CM+ $AL_FOLLOW?;
+^([\p{Pi} & $QU] $CM* $SP*)+ .;
+^([\p{Pi} & $QU] $CM* $SP*)+ $SP $CM+ $AL_FOLLOW?;
+
+# LB 15b
+$LB8NonBreaks [\p{Pf} & $QU] $CM* [$SP $GL $WJ $CL $QU $CP $EX $IS $SY $BK $CR $LF $NL $ZW {eof}];
+$CAN_CM $CM*  [\p{Pf} & $QU] $CM* [$SP $GL $WJ $CL $QU $CP $EX $IS $SY $BK $CR $LF $NL $ZW {eof}];
+^$CM+  [\p{Pf} & $QU] $CM* [$SP $GL $WJ $CL $QU $CP $EX $IS $SY $BK $CR $LF $NL $ZW {eof}];
+
+# Messy interaction: manually chain between LB 15b and LB 15a on Pf Pi.
+$LB8NonBreaks [\p{Pf} & $QU] $CM* ([\p{Pi} & $QU] $CM* $SP*)+ .;
+$LB8NonBreaks [\p{Pf} & $QU] $CM* ([\p{Pi} & $QU] $CM* $SP*)+ $SP $CM+ $AL_FOLLOW?;
+$CAN_CM $CM*  [\p{Pf} & $QU] $CM* ([\p{Pi} & $QU] $CM* $SP*)+ .;
+$CAN_CM $CM*  [\p{Pf} & $QU] $CM* ([\p{Pi} & $QU] $CM* $SP*)+ $SP $CM+ $AL_FOLLOW?;
+^$CM+  [\p{Pf} & $QU] $CM* ([\p{Pi} & $QU] $CM* $SP*)+ .;
+^$CM+  [\p{Pf} & $QU] $CM* ([\p{Pi} & $QU] $CM* $SP*)+ $SP $CM+ $AL_FOLLOW?;
+
+
+# LB 15c Force a break before start of a number with a leading decimal pt, e.g. " .23"
 #        Note: would be simpler to express as "$SP / $IS $CM* $NU;", but ICU rules have limitations.
 #        See issue ICU-20303
 
@@ -232,7 +257,7 @@ $SP $IS           / [^ $CanFollowIS $NU $CM];
 $SP $IS $CM* $CMX / [^ $CanFollowIS $NU $CM];
 
 #
-# LB 14b Do not break before numeric separators (IS), even after spaces.
+# LB 15d Do not break before numeric separators (IS), even after spaces.
 
 [$LB8NonBreaks - $SP] $IS;
 $SP $IS $CM* [$CanFollowIS {eof}];
@@ -242,9 +267,6 @@ $CAN_CM $CM*  $IS;
 ^$CM+         $IS;              # by rule 10, stand-alone CM behaves as AL
 
 
-# LB 15
-$QU $CM* $SP* $OP;
-
 # LB 16
 # Do not break between closing punctuation and $NS, even with intervening spaces
 # But DO allow a break between closing punctuation and $NSX, don't include it here
@@ -349,6 +371,9 @@ $PR $CM* ($JL | $JV | $JT | $H2 | $H3);
 ($ALPlus | $HL) $CM* ($ALPlus | $HL);
 ^$CM+ ($ALPlus | $HL);      # The $CM+ is from rule 10, an unattached CM is treated as AL
 
+#LB 28a  Do not break Orthographic syllables
+($AP $CM*)? ($AS | $AK | [◌] ) ($CM* $VI $CM* ($AK | [◌] ))* ($CM* $VI | (($CM* ($AS | $AK | [◌] ) )? $CM* $VF))?;
+
 # LB 29
 $IS $CM* ($ALPlus | $HL);
 
diff --git a/icu4c/source/data/brkitr/rules/line_loose_cj.txt b/icu4c/source/data/brkitr/rules/line_loose_cj.txt
index 0be1e7cb0c81..1794e77087eb 100644
--- a/icu4c/source/data/brkitr/rules/line_loose_cj.txt
+++ b/icu4c/source/data/brkitr/rules/line_loose_cj.txt
@@ -38,7 +38,10 @@
 !!quoted_literals_only;
 
 $AI = [:LineBreak =  Ambiguous:];
+$AK = [:LineBreak =  Aksara:];
 $AL = [:LineBreak =  Alphabetic:];
+$AP = [:LineBreak =  Aksara_Prebase:];
+$AS = [:LineBreak =  Aksara_Start:];
 $BAX = [\u2010 \u2013];
 $BA = [[:LineBreak =  Break_After:] - $BAX];
 $HH = [\u2010];     # \u2010 is HYPHEN, default line break is BA.
@@ -83,6 +86,8 @@ $SA = [:LineBreak =  Complex_Context:];
 $SG = [:LineBreak =  Surrogate:];
 $SP = [:LineBreak =  Space:];
 $SY = [:LineBreak =  Break_Symbols:];
+$VF = [:LineBreak =  Virama_Final:];
+$VI = [:LineBreak =  Virama:];
 $WJ = [:LineBreak =  Word_Joiner:];
 $XX = [:LineBreak =  Unknown:];
 $ZW = [:LineBreak =  ZWSpace:];
@@ -234,7 +239,27 @@ $OP $CM* $SP+ $CM+ $AL_FOLLOW?;    # by rule 10, stand-alone CM behaves as AL
                                    # by rule 8, CM following a SP is stand-alone.
 
 
-# LB 14a Force a break before start of a number with a leading decimal pt, e.g. " .23"
+# LB 15a
+($OP $CM* $SP+ | [$OP $QU $GL] $CM*) ([\p{Pi} & $QU] $CM* $SP*)+ .;
+($OP $CM* $SP+ | [$OP $QU $GL] $CM*) ([\p{Pi} & $QU] $CM* $SP*)+ $SP $CM+ $AL_FOLLOW?;
+^([\p{Pi} & $QU] $CM* $SP*)+ .;
+^([\p{Pi} & $QU] $CM* $SP*)+ $SP $CM+ $AL_FOLLOW?;
+
+# LB 15b
+$LB8NonBreaks [\p{Pf} & $QU] $CM* [$SP $GL $WJ $CL $QU $CP $EX $IS $SY $BK $CR $LF $NL $ZW {eof}];
+$CAN_CM $CM*  [\p{Pf} & $QU] $CM* [$SP $GL $WJ $CL $QU $CP $EX $IS $SY $BK $CR $LF $NL $ZW {eof}];
+^$CM+  [\p{Pf} & $QU] $CM* [$SP $GL $WJ $CL $QU $CP $EX $IS $SY $BK $CR $LF $NL $ZW {eof}];
+
+# Messy interaction: manually chain between LB 15b and LB 15a on Pf Pi.
+$LB8NonBreaks [\p{Pf} & $QU] $CM* ([\p{Pi} & $QU] $CM* $SP*)+ .;
+$LB8NonBreaks [\p{Pf} & $QU] $CM* ([\p{Pi} & $QU] $CM* $SP*)+ $SP $CM+ $AL_FOLLOW?;
+$CAN_CM $CM*  [\p{Pf} & $QU] $CM* ([\p{Pi} & $QU] $CM* $SP*)+ .;
+$CAN_CM $CM*  [\p{Pf} & $QU] $CM* ([\p{Pi} & $QU] $CM* $SP*)+ $SP $CM+ $AL_FOLLOW?;
+^$CM+  [\p{Pf} & $QU] $CM* ([\p{Pi} & $QU] $CM* $SP*)+ .;
+^$CM+  [\p{Pf} & $QU] $CM* ([\p{Pi} & $QU] $CM* $SP*)+ $SP $CM+ $AL_FOLLOW?;
+
+
+# LB 15c Force a break before start of a number with a leading decimal pt, e.g. " .23"
 #        Note: would be simpler to express as "$SP / $IS $CM* $NU;", but ICU rules have limitations.
 #        See issue ICU-20303
 
@@ -244,7 +269,7 @@ $SP $IS           / [^ $CanFollowIS $NU $CM];
 $SP $IS $CM* $CMX / [^ $CanFollowIS $NU $CM];
 
 #
-# LB 14b Do not break before numeric separators (IS), even after spaces.
+# LB 15d Do not break before numeric separators (IS), even after spaces.
 
 [$LB8NonBreaks - $SP] $IS;
 $SP $IS $CM* [$CanFollowIS {eof}];
@@ -254,9 +279,6 @@ $CAN_CM $CM*  $IS;
 ^$CM+         $IS;              # by rule 10, stand-alone CM behaves as AL
 
 
-# LB 15
-$QU $CM* $SP* $OP;
-
 # LB 16
 # Do not break between closing punctuation and $NS, even with intervening spaces
 # But DO allow a break between closing punctuation and $NSX, don't include it here
@@ -367,6 +389,9 @@ $PR $CM* ($JL | $JV | $JT | $H2 | $H3);
 ($ALPlus | $HL) $CM* ($ALPlus | $HL);
 ^$CM+ ($ALPlus | $HL);      # The $CM+ is from rule 10, an unattached CM is treated as AL
 
+#LB 28a  Do not break Orthographic syllables
+($AP $CM*)? ($AS | $AK | [◌] ) ($CM* $VI $CM* ($AK | [◌] ))* ($CM* $VI | (($CM* ($AS | $AK | [◌] ) )? $CM* $VF))?;
+
 # LB 29
 $IS $CM* ($ALPlus | $HL);
 
diff --git a/icu4c/source/data/brkitr/rules/line_loose_phrase_cj.txt b/icu4c/source/data/brkitr/rules/line_loose_phrase_cj.txt
index 8b37d5acb368..811f4ef71db9 100644
--- a/icu4c/source/data/brkitr/rules/line_loose_phrase_cj.txt
+++ b/icu4c/source/data/brkitr/rules/line_loose_phrase_cj.txt
@@ -40,7 +40,10 @@
 !!quoted_literals_only;
 
 $AI = [:LineBreak =  Ambiguous:];
+$AK = [:LineBreak =  Aksara:];
 $AL = [:LineBreak =  Alphabetic:];
+$AP = [:LineBreak =  Aksara_Prebase:];
+$AS = [:LineBreak =  Aksara_Start:];
 $BAX = [\u2010 \u2013];
 $BA = [[:LineBreak =  Break_After:] - $BAX];
 $HH = [\u2010];     # \u2010 is HYPHEN, default line break is BA.
@@ -85,6 +88,8 @@ $SA = [:LineBreak =  Complex_Context:];
 $SG = [:LineBreak =  Surrogate:];
 $SP = [:LineBreak =  Space:];
 $SY = [:LineBreak =  Break_Symbols:];
+$VF = [:LineBreak =  Virama_Final:];
+$VI = [:LineBreak =  Virama:];
 $WJ = [:LineBreak =  Word_Joiner:];
 $XX = [:LineBreak =  Unknown:];
 $ZW = [:LineBreak =  ZWSpace:];
@@ -247,7 +252,27 @@ $OP $CM* $SP+ $CM+ $AL_FOLLOW?;    # by rule 10, stand-alone CM behaves as AL
                                    # by rule 8, CM following a SP is stand-alone.
 
 
-# LB 14a Force a break before start of a number with a leading decimal pt, e.g. " .23"
+# LB 15a
+($OP $CM* $SP+ | [$OP $QU $GL] $CM*) ([\p{Pi} & $QU] $CM* $SP*)+ .;
+($OP $CM* $SP+ | [$OP $QU $GL] $CM*) ([\p{Pi} & $QU] $CM* $SP*)+ $SP $CM+ $AL_FOLLOW?;
+^([\p{Pi} & $QU] $CM* $SP*)+ .;
+^([\p{Pi} & $QU] $CM* $SP*)+ $SP $CM+ $AL_FOLLOW?;
+
+# LB 15b
+$LB8NonBreaks [\p{Pf} & $QU] $CM* [$SP $GL $WJ $CL $QU $CP $EX $IS $SY $BK $CR $LF $NL $ZW {eof}];
+$CAN_CM $CM*  [\p{Pf} & $QU] $CM* [$SP $GL $WJ $CL $QU $CP $EX $IS $SY $BK $CR $LF $NL $ZW {eof}];
+^$CM+  [\p{Pf} & $QU] $CM* [$SP $GL $WJ $CL $QU $CP $EX $IS $SY $BK $CR $LF $NL $ZW {eof}];
+
+# Messy interaction: manually chain between LB 15b and LB 15a on Pf Pi.
+$LB8NonBreaks [\p{Pf} & $QU] $CM* ([\p{Pi} & $QU] $CM* $SP*)+ .;
+$LB8NonBreaks [\p{Pf} & $QU] $CM* ([\p{Pi} & $QU] $CM* $SP*)+ $SP $CM+ $AL_FOLLOW?;
+$CAN_CM $CM*  [\p{Pf} & $QU] $CM* ([\p{Pi} & $QU] $CM* $SP*)+ .;
+$CAN_CM $CM*  [\p{Pf} & $QU] $CM* ([\p{Pi} & $QU] $CM* $SP*)+ $SP $CM+ $AL_FOLLOW?;
+^$CM+  [\p{Pf} & $QU] $CM* ([\p{Pi} & $QU] $CM* $SP*)+ .;
+^$CM+  [\p{Pf} & $QU] $CM* ([\p{Pi} & $QU] $CM* $SP*)+ $SP $CM+ $AL_FOLLOW?;
+
+
+# LB 15c Force a break before start of a number with a leading decimal pt, e.g. " .23"
 #        Note: would be simpler to express as "$SP / $IS $CM* $NU;", but ICU rules have limitations.
 #        See issue ICU-20303
 
@@ -257,7 +282,7 @@ $SP $IS           / [^ $CanFollowIS $NU $CM];
 $SP $IS $CM* $CMX / [^ $CanFollowIS $NU $CM];
 
 #
-# LB 14b Do not break before numeric separators (IS), even after spaces.
+# LB 15d Do not break before numeric separators (IS), even after spaces.
 
 [$LB8NonBreaks - $SP] $IS;
 $SP $IS $CM* [$CanFollowIS {eof}];
@@ -267,9 +292,6 @@ $CAN_CM $CM*  $IS;
 ^$CM+         $IS;              # by rule 10, stand-alone CM behaves as AL
 
 
-# LB 15
-$QU $CM* $SP* $OP;
-
 # LB 16
 # Do not break between closing punctuation and $NS, even with intervening spaces
 # But DO allow a break between closing punctuation and $NSX, don't include it here
@@ -380,6 +402,9 @@ $PR $CM* ($JL | $JV | $JT | $H2 | $H3);
 ($ALPlus | $HL) $CM* ($ALPlus | $HL);
 ^$CM+ ($ALPlus | $HL);      # The $CM+ is from rule 10, an unattached CM is treated as AL
 
+#LB 28a  Do not break Orthographic syllables
+($AP $CM*)? ($AS | $AK | [◌] ) ($CM* $VI $CM* ($AK | [◌] ))* ($CM* $VI | (($CM* ($AS | $AK | [◌] ) )? $CM* $VF))?;
+
 # LB 29
 $IS $CM* ($ALPlus | $HL);
 
diff --git a/icu4c/source/data/brkitr/rules/line_normal.txt b/icu4c/source/data/brkitr/rules/line_normal.txt
index 70acdb4aed67..a5c6a3dcaa4e 100644
--- a/icu4c/source/data/brkitr/rules/line_normal.txt
+++ b/icu4c/source/data/brkitr/rules/line_normal.txt
@@ -26,7 +26,10 @@
 !!quoted_literals_only;
 
 $AI = [:LineBreak =  Ambiguous:];
+$AK = [:LineBreak =  Aksara:];
 $AL = [:LineBreak =  Alphabetic:];
+$AP = [:LineBreak =  Aksara_Prebase:];
+$AS = [:LineBreak =  Aksara_Start:];
 $BA = [:LineBreak =  Break_After:];
 $HH = [\u2010];     # \u2010 is HYPHEN, default line break is BA.
 $BB = [:LineBreak =  Break_Before:];
@@ -66,6 +69,8 @@ $SA = [:LineBreak =  Complex_Context:];
 $SG = [:LineBreak =  Surrogate:];
 $SP = [:LineBreak =  Space:];
 $SY = [:LineBreak =  Break_Symbols:];
+$VF = [:LineBreak =  Virama_Final:];
+$VI = [:LineBreak =  Virama:];
 $WJ = [:LineBreak =  Word_Joiner:];
 $XX = [:LineBreak =  Unknown:];
 $ZW = [:LineBreak =  ZWSpace:];
@@ -217,7 +222,27 @@ $OP $CM* $SP+ $CM+ $AL_FOLLOW?;    # by rule 10, stand-alone CM behaves as AL
                                    # by rule 8, CM following a SP is stand-alone.
 
 
-# LB 14a Force a break before start of a number with a leading decimal pt, e.g. " .23"
+# LB 15a
+($OP $CM* $SP+ | [$OP $QU $GL] $CM*) ([\p{Pi} & $QU] $CM* $SP*)+ .;
+($OP $CM* $SP+ | [$OP $QU $GL] $CM*) ([\p{Pi} & $QU] $CM* $SP*)+ $SP $CM+ $AL_FOLLOW?;
+^([\p{Pi} & $QU] $CM* $SP*)+ .;
+^([\p{Pi} & $QU] $CM* $SP*)+ $SP $CM+ $AL_FOLLOW?;
+
+# LB 15b
+$LB8NonBreaks [\p{Pf} & $QU] $CM* [$SP $GL $WJ $CL $QU $CP $EX $IS $SY $BK $CR $LF $NL $ZW {eof}];
+$CAN_CM $CM*  [\p{Pf} & $QU] $CM* [$SP $GL $WJ $CL $QU $CP $EX $IS $SY $BK $CR $LF $NL $ZW {eof}];
+^$CM+  [\p{Pf} & $QU] $CM* [$SP $GL $WJ $CL $QU $CP $EX $IS $SY $BK $CR $LF $NL $ZW {eof}];
+
+# Messy interaction: manually chain between LB 15b and LB 15a on Pf Pi.
+$LB8NonBreaks [\p{Pf} & $QU] $CM* ([\p{Pi} & $QU] $CM* $SP*)+ .;
+$LB8NonBreaks [\p{Pf} & $QU] $CM* ([\p{Pi} & $QU] $CM* $SP*)+ $SP $CM+ $AL_FOLLOW?;
+$CAN_CM $CM*  [\p{Pf} & $QU] $CM* ([\p{Pi} & $QU] $CM* $SP*)+ .;
+$CAN_CM $CM*  [\p{Pf} & $QU] $CM* ([\p{Pi} & $QU] $CM* $SP*)+ $SP $CM+ $AL_FOLLOW?;
+^$CM+  [\p{Pf} & $QU] $CM* ([\p{Pi} & $QU] $CM* $SP*)+ .;
+^$CM+  [\p{Pf} & $QU] $CM* ([\p{Pi} & $QU] $CM* $SP*)+ $SP $CM+ $AL_FOLLOW?;
+
+
+# LB 15c Force a break before start of a number with a leading decimal pt, e.g. " .23"
 #        Note: would be simpler to express as "$SP / $IS $CM* $NU;", but ICU rules have limitations.
 #        See issue ICU-20303
 
@@ -227,7 +252,7 @@ $SP $IS           / [^ $CanFollowIS $NU $CM];
 $SP $IS $CM* $CMX / [^ $CanFollowIS $NU $CM];
 
 #
-# LB 14b Do not break before numeric separators (IS), even after spaces.
+# LB 15d Do not break before numeric separators (IS), even after spaces.
 
 [$LB8NonBreaks - $SP] $IS;
 $SP $IS $CM* [$CanFollowIS {eof}];
@@ -237,9 +262,6 @@ $CAN_CM $CM*  $IS;
 ^$CM+         $IS;              # by rule 10, stand-alone CM behaves as AL
 
 
-# LB 15
-$QU $CM* $SP* $OP;
-
 # LB 16
 ($CL | $CP) $CM* $SP* $NS;
 
@@ -340,6 +362,9 @@ $PR $CM* ($JL | $JV | $JT | $H2 | $H3);
 ($ALPlus | $HL) $CM* ($ALPlus | $HL);
 ^$CM+ ($ALPlus | $HL);      # The $CM+ is from rule 10, an unattached CM is treated as AL
 
+#LB 28a  Do not break Orthographic syllables
+($AP $CM*)? ($AS | $AK | [◌] ) ($CM* $VI $CM* ($AK | [◌] ))* ($CM* $VI | (($CM* ($AS | $AK | [◌] ) )? $CM* $VF))?;
+
 # LB 29
 $IS $CM* ($ALPlus | $HL);
 
diff --git a/icu4c/source/data/brkitr/rules/line_normal_cj.txt b/icu4c/source/data/brkitr/rules/line_normal_cj.txt
index 7ed8b35081ab..f9a1e652a641 100644
--- a/icu4c/source/data/brkitr/rules/line_normal_cj.txt
+++ b/icu4c/source/data/brkitr/rules/line_normal_cj.txt
@@ -28,7 +28,10 @@
 !!quoted_literals_only;
 
 $AI = [:LineBreak =  Ambiguous:];
+$AK = [:LineBreak =  Aksara:];
 $AL = [:LineBreak =  Alphabetic:];
+$AP = [:LineBreak =  Aksara_Prebase:];
+$AS = [:LineBreak =  Aksara_Start:];
 $BA = [:LineBreak =  Break_After:];
 $HH = [\u2010];     # \u2010 is HYPHEN, default line break is BA.
 $BB = [:LineBreak =  Break_Before:];
@@ -69,6 +72,8 @@ $SA = [:LineBreak =  Complex_Context:];
 $SG = [:LineBreak =  Surrogate:];
 $SP = [:LineBreak =  Space:];
 $SY = [:LineBreak =  Break_Symbols:];
+$VF = [:LineBreak =  Virama_Final:];
+$VI = [:LineBreak =  Virama:];
 $WJ = [:LineBreak =  Word_Joiner:];
 $XX = [:LineBreak =  Unknown:];
 $ZW = [:LineBreak =  ZWSpace:];
@@ -220,7 +225,27 @@ $OP $CM* $SP+ $CM+ $AL_FOLLOW?;    # by rule 10, stand-alone CM behaves as AL
                                    # by rule 8, CM following a SP is stand-alone.
 
 
-# LB 14a Force a break before start of a number with a leading decimal pt, e.g. " .23"
+# LB 15a
+($OP $CM* $SP+ | [$OP $QU $GL] $CM*) ([\p{Pi} & $QU] $CM* $SP*)+ .;
+($OP $CM* $SP+ | [$OP $QU $GL] $CM*) ([\p{Pi} & $QU] $CM* $SP*)+ $SP $CM+ $AL_FOLLOW?;
+^([\p{Pi} & $QU] $CM* $SP*)+ .;
+^([\p{Pi} & $QU] $CM* $SP*)+ $SP $CM+ $AL_FOLLOW?;
+
+# LB 15b
+$LB8NonBreaks [\p{Pf} & $QU] $CM* [$SP $GL $WJ $CL $QU $CP $EX $IS $SY $BK $CR $LF $NL $ZW {eof}];
+$CAN_CM $CM*  [\p{Pf} & $QU] $CM* [$SP $GL $WJ $CL $QU $CP $EX $IS $SY $BK $CR $LF $NL $ZW {eof}];
+^$CM+  [\p{Pf} & $QU] $CM* [$SP $GL $WJ $CL $QU $CP $EX $IS $SY $BK $CR $LF $NL $ZW {eof}];
+
+# Messy interaction: manually chain between LB 15b and LB 15a on Pf Pi.
+$LB8NonBreaks [\p{Pf} & $QU] $CM* ([\p{Pi} & $QU] $CM* $SP*)+ .;
+$LB8NonBreaks [\p{Pf} & $QU] $CM* ([\p{Pi} & $QU] $CM* $SP*)+ $SP $CM+ $AL_FOLLOW?;
+$CAN_CM $CM*  [\p{Pf} & $QU] $CM* ([\p{Pi} & $QU] $CM* $SP*)+ .;
+$CAN_CM $CM*  [\p{Pf} & $QU] $CM* ([\p{Pi} & $QU] $CM* $SP*)+ $SP $CM+ $AL_FOLLOW?;
+^$CM+  [\p{Pf} & $QU] $CM* ([\p{Pi} & $QU] $CM* $SP*)+ .;
+^$CM+  [\p{Pf} & $QU] $CM* ([\p{Pi} & $QU] $CM* $SP*)+ $SP $CM+ $AL_FOLLOW?;
+
+
+# LB 15c Force a break before start of a number with a leading decimal pt, e.g. " .23"
 #        Note: would be simpler to express as "$SP / $IS $CM* $NU;", but ICU rules have limitations.
 #        See issue ICU-20303
 
@@ -230,7 +255,7 @@ $SP $IS           / [^ $CanFollowIS $NU $CM];
 $SP $IS $CM* $CMX / [^ $CanFollowIS $NU $CM];
 
 #
-# LB 14b Do not break before numeric separators (IS), even after spaces.
+# LB 15d Do not break before numeric separators (IS), even after spaces.
 
 [$LB8NonBreaks - $SP] $IS;
 $SP $IS $CM* [$CanFollowIS {eof}];
@@ -240,9 +265,6 @@ $CAN_CM $CM*  $IS;
 ^$CM+         $IS;              # by rule 10, stand-alone CM behaves as AL
 
 
-# LB 15
-$QU $CM* $SP* $OP;
-
 # LB 16
 # Do not break between closing punctuation and $NS, even with intervening spaces
 # But DO allow a break between closing punctuation and $NSX, don't include it here
@@ -346,6 +368,9 @@ $PR $CM* ($JL | $JV | $JT | $H2 | $H3);
 ($ALPlus | $HL) $CM* ($ALPlus | $HL);
 ^$CM+ ($ALPlus | $HL);      # The $CM+ is from rule 10, an unattached CM is treated as AL
 
+#LB 28a  Do not break Orthographic syllables
+($AP $CM*)? ($AS | $AK | [◌] ) ($CM* $VI $CM* ($AK | [◌] ))* ($CM* $VI | (($CM* ($AS | $AK | [◌] ) )? $CM* $VF))?;
+
 # LB 29
 $IS $CM* ($ALPlus | $HL);
 
diff --git a/icu4c/source/data/brkitr/rules/line_normal_phrase_cj.txt b/icu4c/source/data/brkitr/rules/line_normal_phrase_cj.txt
index 1aeafdf8028d..c8063db60bfe 100644
--- a/icu4c/source/data/brkitr/rules/line_normal_phrase_cj.txt
+++ b/icu4c/source/data/brkitr/rules/line_normal_phrase_cj.txt
@@ -30,7 +30,10 @@
 !!quoted_literals_only;
 
 $AI = [:LineBreak =  Ambiguous:];
+$AK = [:LineBreak =  Aksara:];
 $AL = [:LineBreak =  Alphabetic:];
+$AP = [:LineBreak =  Aksara_Prebase:];
+$AS = [:LineBreak =  Aksara_Start:];
 $BA = [:LineBreak =  Break_After:];
 $HH = [\u2010];     # \u2010 is HYPHEN, default line break is BA.
 $BB = [:LineBreak =  Break_Before:];
@@ -71,6 +74,8 @@ $SA = [:LineBreak =  Complex_Context:];
 $SG = [:LineBreak =  Surrogate:];
 $SP = [:LineBreak =  Space:];
 $SY = [:LineBreak =  Break_Symbols:];
+$VF = [:LineBreak =  Virama_Final:];
+$VI = [:LineBreak =  Virama:];
 $WJ = [:LineBreak =  Word_Joiner:];
 $XX = [:LineBreak =  Unknown:];
 $ZW = [:LineBreak =  ZWSpace:];
@@ -233,7 +238,27 @@ $OP $CM* $SP+ $CM+ $AL_FOLLOW?;    # by rule 10, stand-alone CM behaves as AL
                                    # by rule 8, CM following a SP is stand-alone.
 
 
-# LB 14a Force a break before start of a number with a leading decimal pt, e.g. " .23"
+# LB 15a
+($OP $CM* $SP+ | [$OP $QU $GL] $CM*) ([\p{Pi} & $QU] $CM* $SP*)+ .;
+($OP $CM* $SP+ | [$OP $QU $GL] $CM*) ([\p{Pi} & $QU] $CM* $SP*)+ $SP $CM+ $AL_FOLLOW?;
+^([\p{Pi} & $QU] $CM* $SP*)+ .;
+^([\p{Pi} & $QU] $CM* $SP*)+ $SP $CM+ $AL_FOLLOW?;
+
+# LB 15b
+$LB8NonBreaks [\p{Pf} & $QU] $CM* [$SP $GL $WJ $CL $QU $CP $EX $IS $SY $BK $CR $LF $NL $ZW {eof}];
+$CAN_CM $CM*  [\p{Pf} & $QU] $CM* [$SP $GL $WJ $CL $QU $CP $EX $IS $SY $BK $CR $LF $NL $ZW {eof}];
+^$CM+  [\p{Pf} & $QU] $CM* [$SP $GL $WJ $CL $QU $CP $EX $IS $SY $BK $CR $LF $NL $ZW {eof}];
+
+# Messy interaction: manually chain between LB 15b and LB 15a on Pf Pi.
+$LB8NonBreaks [\p{Pf} & $QU] $CM* ([\p{Pi} & $QU] $CM* $SP*)+ .;
+$LB8NonBreaks [\p{Pf} & $QU] $CM* ([\p{Pi} & $QU] $CM* $SP*)+ $SP $CM+ $AL_FOLLOW?;
+$CAN_CM $CM*  [\p{Pf} & $QU] $CM* ([\p{Pi} & $QU] $CM* $SP*)+ .;
+$CAN_CM $CM*  [\p{Pf} & $QU] $CM* ([\p{Pi} & $QU] $CM* $SP*)+ $SP $CM+ $AL_FOLLOW?;
+^$CM+  [\p{Pf} & $QU] $CM* ([\p{Pi} & $QU] $CM* $SP*)+ .;
+^$CM+  [\p{Pf} & $QU] $CM* ([\p{Pi} & $QU] $CM* $SP*)+ $SP $CM+ $AL_FOLLOW?;
+
+
+# LB 15c Force a break before start of a number with a leading decimal pt, e.g. " .23"
 #        Note: would be simpler to express as "$SP / $IS $CM* $NU;", but ICU rules have limitations.
 #        See issue ICU-20303
 
@@ -243,7 +268,7 @@ $SP $IS           / [^ $CanFollowIS $NU $CM];
 $SP $IS $CM* $CMX / [^ $CanFollowIS $NU $CM];
 
 #
-# LB 14b Do not break before numeric separators (IS), even after spaces.
+# LB 15d Do not break before numeric separators (IS), even after spaces.
 
 [$LB8NonBreaks - $SP] $IS;
 $SP $IS $CM* [$CanFollowIS {eof}];
@@ -253,9 +278,6 @@ $CAN_CM $CM*  $IS;
 ^$CM+         $IS;              # by rule 10, stand-alone CM behaves as AL
 
 
-# LB 15
-$QU $CM* $SP* $OP;
-
 # LB 16
 # Do not break between closing punctuation and $NS, even with intervening spaces
 # But DO allow a break between closing punctuation and $NSX, don't include it here
@@ -359,6 +381,9 @@ $PR $CM* ($JL | $JV | $JT | $H2 | $H3);
 ($ALPlus | $HL) $CM* ($ALPlus | $HL);
 ^$CM+ ($ALPlus | $HL);      # The $CM+ is from rule 10, an unattached CM is treated as AL
 
+#LB 28a  Do not break Orthographic syllables
+($AP $CM*)? ($AS | $AK | [◌] ) ($CM* $VI $CM* ($AK | [◌] ))* ($CM* $VI | (($CM* ($AS | $AK | [◌] ) )? $CM* $VF))?;
+
 # LB 29
 $IS $CM* ($ALPlus | $HL);
 
diff --git a/icu4c/source/data/brkitr/rules/line_phrase_cj.txt b/icu4c/source/data/brkitr/rules/line_phrase_cj.txt
index 290b9b8c83a7..e23de7474c63 100644
--- a/icu4c/source/data/brkitr/rules/line_phrase_cj.txt
+++ b/icu4c/source/data/brkitr/rules/line_phrase_cj.txt
@@ -26,7 +26,10 @@
 !!quoted_literals_only;
 
 $AI = [:LineBreak =  Ambiguous:];
+$AK = [:LineBreak =  Aksara:];
 $AL = [:LineBreak =  Alphabetic:];
+$AP = [:LineBreak =  Aksara_Prebase:];
+$AS = [:LineBreak =  Aksara_Start:];
 $BA = [:LineBreak =  Break_After:];
 $HH = [\u2010];     # \u2010 is HYPHEN, default line break is BA.
 $BB = [:LineBreak =  Break_Before:];
@@ -66,6 +69,8 @@ $SA = [:LineBreak =  Complex_Context:];
 $SG = [:LineBreak =  Surrogate:];
 $SP = [:LineBreak =  Space:];
 $SY = [:LineBreak =  Break_Symbols:];
+$VF = [:LineBreak =  Virama_Final:];
+$VI = [:LineBreak =  Virama:];
 $WJ = [:LineBreak =  Word_Joiner:];
 $XX = [:LineBreak =  Unknown:];
 $ZW = [:LineBreak =  ZWSpace:];
@@ -228,7 +233,27 @@ $OP $CM* $SP+ $CM+ $AL_FOLLOW?;    # by rule 10, stand-alone CM behaves as AL
                                    # by rule 8, CM following a SP is stand-alone.
 
 
-# LB 14a Force a break before start of a number with a leading decimal pt, e.g. " .23"
+# LB 15a
+($OP $CM* $SP+ | [$OP $QU $GL] $CM*) ([\p{Pi} & $QU] $CM* $SP*)+ .;
+($OP $CM* $SP+ | [$OP $QU $GL] $CM*) ([\p{Pi} & $QU] $CM* $SP*)+ $SP $CM+ $AL_FOLLOW?;
+^([\p{Pi} & $QU] $CM* $SP*)+ .;
+^([\p{Pi} & $QU] $CM* $SP*)+ $SP $CM+ $AL_FOLLOW?;
+
+# LB 15b
+$LB8NonBreaks [\p{Pf} & $QU] $CM* [$SP $GL $WJ $CL $QU $CP $EX $IS $SY $BK $CR $LF $NL $ZW {eof}];
+$CAN_CM $CM*  [\p{Pf} & $QU] $CM* [$SP $GL $WJ $CL $QU $CP $EX $IS $SY $BK $CR $LF $NL $ZW {eof}];
+^$CM+  [\p{Pf} & $QU] $CM* [$SP $GL $WJ $CL $QU $CP $EX $IS $SY $BK $CR $LF $NL $ZW {eof}];
+
+# Messy interaction: manually chain between LB 15b and LB 15a on Pf Pi.
+$LB8NonBreaks [\p{Pf} & $QU] $CM* ([\p{Pi} & $QU] $CM* $SP*)+ .;
+$LB8NonBreaks [\p{Pf} & $QU] $CM* ([\p{Pi} & $QU] $CM* $SP*)+ $SP $CM+ $AL_FOLLOW?;
+$CAN_CM $CM*  [\p{Pf} & $QU] $CM* ([\p{Pi} & $QU] $CM* $SP*)+ .;
+$CAN_CM $CM*  [\p{Pf} & $QU] $CM* ([\p{Pi} & $QU] $CM* $SP*)+ $SP $CM+ $AL_FOLLOW?;
+^$CM+  [\p{Pf} & $QU] $CM* ([\p{Pi} & $QU] $CM* $SP*)+ .;
+^$CM+  [\p{Pf} & $QU] $CM* ([\p{Pi} & $QU] $CM* $SP*)+ $SP $CM+ $AL_FOLLOW?;
+
+
+# LB 15c Force a break before start of a number with a leading decimal pt, e.g. " .23"
 #        Note: would be simpler to express as "$SP / $IS $CM* $NU;", but ICU rules have limitations.
 #        See issue ICU-20303
 
@@ -238,7 +263,7 @@ $SP $IS           / [^ $CanFollowIS $NU $CM];
 $SP $IS $CM* $CMX / [^ $CanFollowIS $NU $CM];
 
 #
-# LB 14b Do not break before numeric separators (IS), even after spaces.
+# LB 15d Do not break before numeric separators (IS), even after spaces.
 
 [$LB8NonBreaks - $SP] $IS;
 $SP $IS $CM* [$CanFollowIS {eof}];
@@ -248,9 +273,6 @@ $CAN_CM $CM*  $IS;
 ^$CM+         $IS;              # by rule 10, stand-alone CM behaves as AL
 
 
-# LB 15
-$QU $CM* $SP* $OP;
-
 # LB 16
 ($CL | $CP) $CM* $SP* $NS;
 
@@ -351,6 +373,9 @@ $PR $CM* ($JL | $JV | $JT | $H2 | $H3);
 ($ALPlus | $HL) $CM* ($ALPlus | $HL);
 ^$CM+ ($ALPlus | $HL);      # The $CM+ is from rule 10, an unattached CM is treated as AL
 
+#LB 28a  Do not break Orthographic syllables
+($AP $CM*)? ($AS | $AK | [◌] ) ($CM* $VI $CM* ($AK | [◌] ))* ($CM* $VI | (($CM* ($AS | $AK | [◌] ) )? $CM* $VF))?;
+
 # LB 29
 $IS $CM* ($ALPlus | $HL);
 
diff --git a/icu4c/source/test/intltest/rbbitst.cpp b/icu4c/source/test/intltest/rbbitst.cpp
index 8d4ddfe7bd9c..5d54b47ecb17 100644
--- a/icu4c/source/test/intltest/rbbitst.cpp
+++ b/icu4c/source/test/intltest/rbbitst.cpp
@@ -15,6 +15,7 @@
 #if !UCONFIG_NO_BREAK_ITERATION
 
 #include <algorithm>
+#include <set>
 #include <sstream>
 #include <stdio.h>
 #include <stdlib.h>
@@ -1453,21 +1454,29 @@ void RBBITest::checkUnicodeTestCase(const char *testFileName, int lineNumber,
     pos = bi->first();
     pos = bi->next();
 
+    bool error = false;
+    std::set<int32_t> actualBreaks;
+    std::set<int32_t> expectedBreaks;
     while (pos != BreakIterator::DONE) {
+        actualBreaks.insert(pos);
         if (expectedI >= breakPositions->size()) {
             errln("Test file \"%s\", line %d, unexpected break found at position %d",
                 testFileName, lineNumber, pos);
+            error = true;
             break;
         }
         expectedPos = breakPositions->elementAti(expectedI);
+        expectedBreaks.insert(expectedPos);
         if (pos < expectedPos) {
-            errln("Test file \"%s\", line %d, unexpected break found at position %d",
-                testFileName, lineNumber, pos);
+            errln("Test file \"%s\", line %d, unexpected break found at position %d", testFileName,
+                  lineNumber, pos);
+            error = true;
             break;
         }
         if (pos > expectedPos) {
             errln("Test file \"%s\", line %d, failed to find expected break at position %d",
-                testFileName, lineNumber, expectedPos);
+                  testFileName, lineNumber, expectedPos);
+            error = true;
             break;
         }
         pos = bi->next();
@@ -1475,8 +1484,32 @@ void RBBITest::checkUnicodeTestCase(const char *testFileName, int lineNumber,
     }
 
     if (pos==BreakIterator::DONE && expectedI<breakPositions->size()) {
-        errln("Test file \"%s\", line %d, failed to find expected break at position %d",
-            testFileName, lineNumber, breakPositions->elementAti(expectedI));
+        errln("Test file \"%s\", line %d, failed to find expected break at position %d", testFileName,
+              lineNumber, breakPositions->elementAti(expectedI));
+        error = true;
+    }
+
+    if (error) {
+        for (; pos != BreakIterator::DONE; pos = bi->next()) {
+            actualBreaks.insert(pos);
+        }
+        for (; expectedI < breakPositions->size(); ++expectedI) {
+            expectedBreaks.insert(breakPositions->elementAti(expectedI));
+        }
+        UnicodeString expected;
+        UnicodeString actual;
+        for (int32_t i = 0; i < testString.length();) {
+            const UChar32 c = testString.char32At(i);
+            i += U16_LENGTH(c);
+            expected += expectedBreaks.count(i) == 1 ? "÷" : "×";
+            actual += actualBreaks.count(i) == 1 ? "÷" : "×";
+            expected += c;
+            actual += c;
+        }
+        expected += expectedBreaks.count(testString.length()) == 1 ? "÷" : "×";
+        actual += actualBreaks.count(testString.length()) == 1 ? "÷" : "×";
+        errln("Expected : " + expected);
+        errln("Actual   : " + actual);
     }
 }
 
@@ -2662,6 +2695,8 @@ class RBBILineMonkey: public RBBIMonkeyKind {
     UnicodeSet  *fAS;
     UnicodeSet  *fVF;
     UnicodeSet  *fVI;
+    UnicodeSet  *fPi;
+    UnicodeSet  *fPf;
 
     BreakIterator        *fCharBI;
     const UnicodeString  *fText;
@@ -2732,15 +2767,14 @@ RBBILineMonkey::RBBILineMonkey() :
     fCP30  = new UnicodeSet(u"[\\p{Line_break=CP}-[\\p{ea=F}\\p{ea=W}\\p{ea=H}]]", status);
     fExtPictUnassigned = new UnicodeSet(u"[\\p{Extended_Pictographic}&\\p{Cn}]", status);
 
-    fAK    = new UnicodeSet(
-        u"[\u1B05-\u1B33\u1B45-\u1B4C\u25CC\uA984-\uA9B2\U00011005-\U00011037\U00011071-\U00011072\U00011075\U00011305-\U0001130C\U0001130F-\U00011310\U00011313-\U00011328\U0001132A-\U00011330\U00011332-\U00011333\U00011335-\U00011339\U00011360-\U00011361\U00011392-\U000113B5\U00011F04-\U00011F10\U00011F12-\U00011F33]",
-        status);
-    fAP    = new UnicodeSet(u"[\U00011003-\U00011004\U000113D1\U00011F02]", status);
-    fAS    = new UnicodeSet(
-        u"[\u1BC0-\u1BE5\uAA00-\uAA28\U00011066-\U0001106F\U00011350\U0001135E-\U0001135F\U00011380-\U00011389\U0001138B\U0001138E\U00011390-\U00011391\U00011EE0-\U00011EF1\U00011F50-\U00011F59]",
-        status);
-    fVF = new UnicodeSet(u"[\u1BF2-\u1BF3]", status);
-    fVI = new UnicodeSet(u"[\u1B44\uA9C0\U00011046\U0001134D\U000113D0\U00011F42]", status);
+    fAK = new UnicodeSet(uR"([\p{Line_Break=AK}])", status);
+    fAP = new UnicodeSet(uR"([\p{Line_Break=AP}])", status);
+    fAS = new UnicodeSet(uR"([\p{Line_Break=AS}])", status);
+    fVF = new UnicodeSet(uR"([\p{Line_Break=VF}])", status);
+    fVI = new UnicodeSet(uR"([\p{Line_Break=VI}])", status);
+
+    fPi = new UnicodeSet(uR"([\p{Pi}])", status);
+    fPf = new UnicodeSet(uR"([\p{Pf}])", status);
 
     if (U_FAILURE(status)) {
         deferredStatus = status;
@@ -2756,12 +2790,6 @@ RBBILineMonkey::RBBILineMonkey() :
 
     fHH->add(u'\u2010');   // Hyphen, '‐'
 
-    fAL->removeAll(*fAK);
-    fAL->removeAll(*fAP);
-    fAL->removeAll(*fAS);
-    fCM->removeAll(*fVF);
-    fCM->removeAll(*fVI);
-
     // Sets and names.
     fSets->addElement(fBK, status); classNames.push_back("fBK");
     fSets->addElement(fCR, status); classNames.push_back("fCR");
@@ -2814,10 +2842,7 @@ RBBILineMonkey::RBBILineMonkey() :
     fSets->addElement(fVI, status); classNames.push_back("fVI");
 
 
-    // Hack for orthographic syllable prototype, to adjust CM property for use in numeric regexp.
-    //    Note that 200d adjustment is permanent.
-
-    UnicodeString CMx {u"[[[\\p{Line_Break=CM}]\\u200d]-[\\u1BF2-\\u1BF3\\u1B44\\uA9C0\\U00011046\\U0001134D\\U000113D0\\U00011F42]]"};
+    UnicodeString CMx {uR"([[\p{Line_Break=CM}]\u200d])"};
     UnicodeString rules;
     rules = rules + u"((\\p{Line_Break=PR}|\\p{Line_Break=PO})(" + CMx + u")*)?"
                   + u"((\\p{Line_Break=OP}|\\p{Line_Break=HY})(" + CMx + u")*)?"
@@ -3119,39 +3144,72 @@ int32_t RBBILineMonkey::next(int32_t startPos) {
             continue;
         }
 
-
-        if (nextPos < fText->length()) {
-            // note: UnicodeString::char32At(length) returns ffff, not distinguishable
-            //       from a legit ffff character. So test length separately.
-            UChar32 nextChar = fText->char32At(nextPos);
-            if (fSP->contains(prevChar) && fIS->contains(thisChar) && fNU->contains(nextChar)) {
-                setAppliedRule(pos, "LB 14a Break before an IS that begins a number and follows a space");
-                break;
+        // Same as LB 14, scan backward for
+        // (sot | BK | CR | LF | NL | OP CM*| QU CM* | GL CM* | SP) [\p{Pi}&QU] CM* SP*.
+        tPos = prevPos;
+        // SP* (with the aforementioned Twist).
+        if (fSP->contains(prevChar)) {
+            while (tPos > 0 && fSP->contains(fText->char32At(tPos))) {
+                tPos = fText->moveIndex32(tPos, -1);
             }
         }
-
-
-          if (fIS->contains(thisChar)) {
-              setAppliedRule(pos, "LB 14b  Do not break before numeric separators, even after spaces.");
-              continue;
+        // CM*.
+        while (tPos > 0 && fCM->contains(fText->char32At(tPos))) {
+            tPos = fText->moveIndex32(tPos, -1);
         }
-
-
-        if (fOP->contains(thisChar)) {
-            // Scan backwards from prevChar to see if it is preceded by QU CM* SP*
-            int tPos = prevPos;
-            while (tPos>0 && fSP->contains(fText->char32At(tPos))) {
+        // [\p{Pi}&QU].
+        if (fPi->contains(fText->char32At(tPos)) && fQU->contains(fText->char32At(tPos))) {
+            if (tPos == 0) {
+                setAppliedRule(pos, "LB 15a sot [\\p{Pi}&QU] SP* ×");
+                continue;
+            } else {
                 tPos = fText->moveIndex32(tPos, -1);
+                if (fBK->contains(fText->char32At(tPos)) || fCR->contains(fText->char32At(tPos)) ||
+                    fLF->contains(fText->char32At(tPos)) || fNL->contains(fText->char32At(tPos)) ||
+                    fSP->contains(fText->char32At(tPos)) || fZW->contains(fText->char32At(tPos))) {
+                    setAppliedRule(pos, "LB 15a (BK | CR | LF | NL | SP | ZW) [\\p{Pi}&QU] SP* ×");
+                    continue;
+                }
             }
-            while (tPos>0 && fCM->contains(fText->char32At(tPos))) {
+            // CM*.
+            while (tPos > 0 && fCM->contains(fText->char32At(tPos))) {
                 tPos = fText->moveIndex32(tPos, -1);
             }
-            if (fQU->contains(fText->char32At(tPos))) {
-                setAppliedRule(pos, "LB 15    QU SP* x OP");
+            if (fOP->contains(fText->char32At(tPos)) || fQU->contains(fText->char32At(tPos)) ||
+                fGL->contains(fText->char32At(tPos))) {
+                setAppliedRule(pos, "LB 15a (OP | QU | GL) [\\p{Pi}&QU] SP* ×");
                 continue;
             }
         }
 
+        if (fPf->contains(thisChar) && fQU->contains(thisChar)) {
+            UChar32 nextChar = fText->char32At(nextPos);
+            if (nextPos == fText->length() || fSP->contains(nextChar) || fGL->contains(nextChar) ||
+                fWJ->contains(nextChar) || fCL->contains(nextChar) || fQU->contains(nextChar) ||
+                fCP->contains(nextChar) || fEX->contains(nextChar) || fIS->contains(nextChar) ||
+                fSY->contains(nextChar) || fBK->contains(nextChar) || fCR->contains(nextChar) ||
+                fLF->contains(nextChar) || fNL->contains(nextChar) || fZW->contains(nextChar)) {
+                setAppliedRule(pos, "LB 15b × [\\p{Pf}&QU] ( SP | GL | WJ | CL | QU | CP | EX | IS | SY "
+                                    "| BK | CR | LF | NL | ZW | eot)");
+                continue;
+            }
+        }
+
+        if (nextPos < fText->length()) {
+            // note: UnicodeString::char32At(length) returns ffff, not distinguishable
+            //       from a legit ffff noncharacter. So test length separately.
+            UChar32 nextChar = fText->char32At(nextPos);
+            if (fSP->contains(prevChar) && fIS->contains(thisChar) && fNU->contains(nextChar)) {
+                setAppliedRule(pos,
+                               "LB 15c Break before an IS that begins a number and follows a space");
+                break;
+            }
+        }
+
+        if (fIS->contains(thisChar)) {
+            setAppliedRule(pos, "LB 15d  Do not break before numeric separators, even after spaces.");
+            continue;
+        }
 
         //    Scan backwards for SP* CM* (CL | CP)
         if (fNS->contains(thisChar)) {
@@ -3313,36 +3371,38 @@ int32_t RBBILineMonkey::next(int32_t startPos) {
         }
 
 
-
         if ((fAL->contains(prevChar) || fHL->contains(prevChar)) && (fAL->contains(thisChar) || fHL->contains(thisChar))) {
             setAppliedRule(pos, "LB 28  Do not break between alphabetics (\"at\").");
             continue;
         }
 
-        if (fAP->contains(prevChar) && (fAK->contains(thisChar) || fAS->contains(thisChar))) {
-            setAppliedRule(pos, "LB 28b.1  AP x (AK | AS)");
+        if (fAP->contains(prevChar) &&
+            (fAK->contains(thisChar) || thisChar == U'◌' || fAS->contains(thisChar))) {
+            setAppliedRule(pos, "LB 28a.1  AP x (AK | ◌ | AS)");
             continue;
         }
 
-        if ((fAK->contains(prevChar) || fAS->contains(prevChar)) &&
+        if ((fAK->contains(prevChar) || prevChar == U'◌' || fAS->contains(prevChar)) &&
             (fVF->contains(thisChar) || fVI->contains(thisChar))) {
-            setAppliedRule(pos, "LB 28b.2  (AK | AS) x (VF | VI)");
+            setAppliedRule(pos, "LB 28a.2  (AK | ◌ | AS) x (VF | VI)");
             continue;
         }
 
-        if ((fAK->contains(prevCharX2) || fAS->contains(prevCharX2)) &&
-            fVI->contains(prevChar) && fAK->contains(thisChar)) {
-            setAppliedRule(pos, "LB 28b.3  (AK | AS) VI x AK");
+        if ((fAK->contains(prevCharX2) || prevCharX2 == U'◌' || fAS->contains(prevCharX2)) &&
+            fVI->contains(prevChar) &&
+            (fAK->contains(thisChar) || thisChar == U'◌')) {
+            setAppliedRule(pos, "LB 28a.3  (AK | ◌ | AS) VI x (AK | ◌)");
             continue;
         }
 
         if (nextPos < fText->length()) {
             // note: UnicodeString::char32At(length) returns ffff, not distinguishable
-            //       from a legit ffff character. So test length separately.
+            //       from a legit ffff noncharacter. So test length separately.
             UChar32 nextChar = fText->char32At(nextPos);
-            if ((fAK->contains(prevChar) || fAS->contains(prevChar)) &&
-                (fAK->contains(thisChar) || fAS->contains(thisChar)) && fVF->contains(nextChar)) {
-                setAppliedRule(pos, "LB 28b.4  (AK | AS) x (AK | AS) VF");
+            if ((fAK->contains(prevChar) || prevChar == U'◌' || fAS->contains(prevChar)) &&
+                (fAK->contains(thisChar) || thisChar == U'◌' || fAS->contains(thisChar)) &&
+                fVF->contains(nextChar)) {
+                setAppliedRule(pos, "LB 28a.4  (AK | ◌ | AS) x (AK | ◌ | AS) VF");
                 continue;
             }
         }
@@ -3455,6 +3515,8 @@ RBBILineMonkey::~RBBILineMonkey() {
     delete fAS;
     delete fVF;
     delete fVI;
+    delete fPi;
+    delete fPf;
 
     delete fCharBI;
     delete fNumberMatcher;
@@ -4269,7 +4331,7 @@ void RBBITest::RunMonkey(BreakIterator *bi, RBBIMonkeyKind &mk, const char *name
                        "Break found but not expected"),
                     name, i, seed);
 
-                for (ci=startContext; (ci = testText.moveIndex32(ci, 1));) {
+                for (ci = startContext;; (ci = testText.moveIndex32(ci, 1))) {
                     UChar32  c;
                     c = testText.char32At(ci);
 
diff --git a/icu4c/source/test/testdata/break_rules/line.txt b/icu4c/source/test/testdata/break_rules/line.txt
index 409f223ed6f4..c68a66b95f20 100644
--- a/icu4c/source/test/testdata/break_rules/line.txt
+++ b/icu4c/source/test/testdata/break_rules/line.txt
@@ -24,7 +24,10 @@ locale = en;
 
 
 AI = [:LineBreak =  Ambiguous:];
+AK = [:LineBreak =  Aksara:];
 AL = [:LineBreak =  Alphabetic:];
+AP = [:LineBreak =  Aksara_Prebase:];
+AS = [:LineBreak =  Aksara_Start:];
 BA = [:LineBreak =  Break_After:];
 HH = [\u2010];      # \u2010 is HYPHEN, default line break is BA.
 BB = [:LineBreak =  Break_Before:];
@@ -63,6 +66,8 @@ SA = [:LineBreak =  Complex_Context:];
 SG = [:LineBreak =  Surrogate:];
 SP = [:LineBreak =  Space:];
 SY = [:LineBreak =  Break_Symbols:];
+VF = [:LineBreak =  Virama_Final:];
+VI = [:LineBreak =  Virama:];
 WJ = [:LineBreak =  Word_Joiner:];
 XX = [:LineBreak =  Unknown:];
 ZW = [:LineBreak =  ZWSpace:];
@@ -75,6 +80,9 @@ ZWJ = [:LineBreak =  ZWJ:];
 OP30 = [OP - [\p{ea=F}\p{ea=W}\p{ea=H}]];
 CP30 = [CP - [\p{ea=F}\p{ea=W}\p{ea=H}]];
 
+PiQU = [\p{Pi}&QU];
+PfQU = [\p{Pf}&QU];
+
 # The redundant-looking inner brackets are required for the current parser in the test code.
 ExtPictUnassigned = [[\p{Extended_Pictographic}]&[\p{Cn}]];
 
@@ -106,19 +114,27 @@ LB8:        ZW SP* ÷ [^ZW SP BK CR LF NL];
 LB25:        ((PR | PO)CM*)? ((OP | HY)CM*)? (IS CM*)? NU (CM*(NU | SY | IS))* (CM*(CL | CP))? (CM*(PR | PO))?;
 
 # Rules LB14 - LB17.
+
+# Moved before LB14, because it matches a supersequence.
+LB15a.1:       ( OP CM* SP* | QU CM* | GL CM* ) (PiQU CM* SP*)+ .;
+
 # Moved up, before LB7, because they can match a longer sequence that would also match LB7.
 # For example, the sequence "OP CM SP AL" matches LB14
 # while the prefix of it, "OP CM SP" matches LB7.1
 LB14:        OP CM* SP* .;
 
-# LB 14a Break before an IS that begins a number and follows a space.
-LB14a:       SP ÷ IS CM* NU;
+LB15a.2:       ^ (PiQU CM* SP*)+ .;
+# LB15b/LB15a chaining.
+LB15b.1:       ([^SP] CM* | SP) PfQU CM* (PiQU CM* SP*)+ .;
+LB15b.2:       ([^SP] CM* | SP) PfQU CM* ( SP | GL | WJ | CL | QU | CP | EX | IS | SY | BK | CR | LF | NL | ZW | $ );
 
-# LB14b       × IS
-LB14b.1:     [^SP] CM* IS;
-LB14b.2:     SP IS;
+# LB 15c Break before an IS that begins a number and follows a space.
+LB15c:       SP ÷ IS CM* NU;
+
+# LB15d       × IS
+LB15d.1:     [^SP] CM* IS;
+LB15d.2:     SP IS;
 
-LB15:        QU CM* SP* OP;
 LB16:        (CL | CP)CM* SP* NS;
 LB17:        B2 CM* SP* B2;
 
@@ -205,6 +221,8 @@ LB27.2:      PR CM* (JL | JV | JT | H2 | H3);
 #      Unattached (leading) CM treated as AL.
 LB28:        (AL | HL | CM)CM* (AL | HL);
 
+LB28: (AP CM*)? (AS | AK | [◌] ) (CM* VI CM* (AK | [◌] ))* (CM* VI | ((CM* (AS | AK | [◌] ) )? CM* VF))?;
+
 LB29:        IS CM* (AL | HL);
 
 # LB30  is adjusted for unattached leading CM being treated as AL.
diff --git a/icu4c/source/test/testdata/break_rules/line_cj.txt b/icu4c/source/test/testdata/break_rules/line_cj.txt
index e66b0d134ada..bcfc94f05485 100644
--- a/icu4c/source/test/testdata/break_rules/line_cj.txt
+++ b/icu4c/source/test/testdata/break_rules/line_cj.txt
@@ -17,7 +17,10 @@ locale = zh;
 
 
 AI = [:LineBreak =  Ambiguous:];
+AK = [:LineBreak =  Aksara:];
 AL = [:LineBreak =  Alphabetic:];
+AP = [:LineBreak =  Aksara_Prebase:];
+AS = [:LineBreak =  Aksara_Start:];
 BA = [:LineBreak =  Break_After:];
 HH = [\u2010];      # \u2010 is HYPHEN, default line break is BA.
 BB = [:LineBreak =  Break_Before:];
@@ -56,6 +59,8 @@ SA = [:LineBreak =  Complex_Context:];
 SG = [:LineBreak =  Surrogate:];
 SP = [:LineBreak =  Space:];
 SY = [:LineBreak =  Break_Symbols:];
+VF = [:LineBreak =  Virama_Final:];
+VI = [:LineBreak =  Virama:];
 WJ = [:LineBreak =  Word_Joiner:];
 XX = [:LineBreak =  Unknown:];
 ZW = [:LineBreak =  ZWSpace:];
@@ -75,6 +80,9 @@ CP30 = [CP - [\p{ea=F}\p{ea=W}\p{ea=H}]];
 OP30 = [OP - [\p{ea=F}\p{ea=W}\p{ea=H}]];
 CP30 = [CP - [\p{ea=F}\p{ea=W}\p{ea=H}]];
 
+PiQU = [\p{Pi}&QU];
+PfQU = [\p{Pf}&QU];
+
 # The redundant-looking inner brackets are required for the current parser in the test code.
 ExtPictUnassigned = [[\p{Extended_Pictographic}]&[\p{Cn}]];
 
@@ -106,19 +114,27 @@ LB8:        ZW SP* ÷ [^ZW SP BK CR LF NL];
 LB25:        ((PR | PO)CM*)? ((OP | HY)CM*)? (IS CM*)? NU (CM*(NU | SY | IS))* (CM*(CL | CP))? (CM*(PR | PO))?;
 
 # Rules LB14 - LB17.
+
+# Moved before LB14, because it matches a supersequence.
+LB15a.1:       ( OP CM* SP* | QU CM* | GL CM* ) (PiQU CM* SP*)+ .;
+
 # Moved up, before LB7, because they can match a longer sequence that would also match LB7.
 # For example, the sequence "OP CM SP AL" matches LB14
 # while the prefix of it, "OP CM SP" matches LB7.1
 LB14:        OP CM* SP* .;
 
-# LB 14a Break before an IS that begins a number and follows a space.
-LB14a:       SP ÷ IS CM* NU;
+LB15a.2:       ^ (PiQU CM* SP*)+ .;
+# LB15b/LB15a chaining.
+LB15b.1:       ([^SP] CM* | SP) PfQU CM* (PiQU CM* SP*)+ .;
+LB15b.2:       ([^SP] CM* | SP) PfQU CM* ( SP | GL | WJ | CL | QU | CP | EX | IS | SY | BK | CR | LF | NL | ZW | $ );
 
-# LB14b       × IS
-LB14b.1:     [^SP] CM* IS;
-LB14b.2:     SP IS;
+# LB 15c Break before an IS that begins a number and follows a space.
+LB15c:       SP ÷ IS CM* NU;
+
+# LB15d       × IS
+LB15d.1:     [^SP] CM* IS;
+LB15d.2:     SP IS;
 
-LB15:        QU CM* SP* OP;
 LB16:        (CL | CP)CM* SP* NS;
 LB17:        B2 CM* SP* B2;
 
@@ -205,6 +221,8 @@ LB27.2:      PR CM* (JL | JV | JT | H2 | H3);
 #      Unattached (leading) CM treated as AL.
 LB28:        (AL | HL | CM)CM* (AL | HL);
 
+LB28: (AP CM*)? (AS | AK | [◌] ) (CM* VI CM* (AK | [◌] ))* (CM* VI | ((CM* (AS | AK | [◌] ) )? CM* VF))?;
+
 LB29:        IS CM* (AL | HL);
 
 # LB30  is adjusted for unattached leading CM being treated as AL.
diff --git a/icu4c/source/test/testdata/break_rules/line_loose.txt b/icu4c/source/test/testdata/break_rules/line_loose.txt
index 54873a489698..05c2bea74025 100644
--- a/icu4c/source/test/testdata/break_rules/line_loose.txt
+++ b/icu4c/source/test/testdata/break_rules/line_loose.txt
@@ -24,7 +24,10 @@ locale = en@lb=loose;
 
 
 AI = [:LineBreak =  Ambiguous:];
+AK = [:LineBreak =  Aksara:];
 AL = [:LineBreak =  Alphabetic:];
+AP = [:LineBreak =  Aksara_Prebase:];
+AS = [:LineBreak =  Aksara_Start:];
 BA = [:LineBreak =  Break_After:];
 HH = [\u2010];      # \u2010 is HYPHEN, default line break is BA.
 BB = [:LineBreak =  Break_Before:];
@@ -64,6 +67,8 @@ SA = [:LineBreak =  Complex_Context:];
 SG = [:LineBreak =  Surrogate:];
 SP = [:LineBreak =  Space:];
 SY = [:LineBreak =  Break_Symbols:];
+VF = [:LineBreak =  Virama_Final:];
+VI = [:LineBreak =  Virama:];
 WJ = [:LineBreak =  Word_Joiner:];
 XX = [:LineBreak =  Unknown:];
 ZW = [:LineBreak =  ZWSpace:];
@@ -76,6 +81,9 @@ ZWJ = [:LineBreak =  ZWJ:];
 OP30 = [OP - [\p{ea=F}\p{ea=W}\p{ea=H}]];
 CP30 = [CP - [\p{ea=F}\p{ea=W}\p{ea=H}]];
 
+PiQU = [\p{Pi}&QU];
+PfQU = [\p{Pf}&QU];
+
 # The redundant-looking inner brackets are required for the current parser in the test code.
 ExtPictUnassigned = [[\p{Extended_Pictographic}]&[\p{Cn}]];
 
@@ -107,19 +115,27 @@ LB8:        ZW SP* ÷ [^ZW SP BK CR LF NL];
 LB25:        ((PR | PO)CM*)? ((OP | HY)CM*)? (IS CM*)? NU (CM*(NU | SY | IS))* (CM*(CL | CP))? (CM*(PR | PO))?;
 
 # Rules LB14 - LB17.
+
+# Moved before LB14, because it matches a supersequence.
+LB15a.1:       ( OP CM* SP* | QU CM* | GL CM* ) (PiQU CM* SP*)+ .;
+
 # Moved up, before LB7, because they can match a longer sequence that would also match LB7.
 # For example, the sequence "OP CM SP AL" matches LB14
 # while the prefix of it, "OP CM SP" matches LB7.1
 LB14:        OP CM* SP* .;
 
-# LB 14a Break before an IS that begins a number and follows a space.
-LB14a:       SP ÷ IS CM* NU;
+LB15a.2:       ^ (PiQU CM* SP*)+ .;
+# LB15b/LB15a chaining.
+LB15b.1:       ([^SP] CM* | SP) PfQU CM* (PiQU CM* SP*)+ .;
+LB15b.2:       ([^SP] CM* | SP) PfQU CM* ( SP | GL | WJ | CL | QU | CP | EX | IS | SY | BK | CR | LF | NL | ZW | $ );
 
-# LB14b       × IS
-LB14b.1:     [^SP] CM* IS;
-LB14b.2:     SP IS;
+# LB 15c Break before an IS that begins a number and follows a space.
+LB15c:       SP ÷ IS CM* NU;
+
+# LB15d       × IS
+LB15d.1:     [^SP] CM* IS;
+LB15d.2:     SP IS;
 
-LB15:        QU CM* SP* OP;
 LB16:        (CL | CP)CM* SP* NS;
 LB17:        B2 CM* SP* B2;
 
@@ -207,6 +223,8 @@ LB27.2:      PR CM* (JL | JV | JT | H2 | H3);
 #      Unattached (leading) CM treated as AL.
 LB28:        (AL | HL | CM)CM* (AL | HL);
 
+LB28: (AP CM*)? (AS | AK | [◌] ) (CM* VI CM* (AK | [◌] ))* (CM* VI | ((CM* (AS | AK | [◌] ) )? CM* VF))?;
+
 LB29:        IS CM* (AL | HL);
 
 # LB30  is adjusted for unattached leading CM being treated as AL.
diff --git a/icu4c/source/test/testdata/break_rules/line_loose_cj.txt b/icu4c/source/test/testdata/break_rules/line_loose_cj.txt
index 9d7b2cc12c6d..93a06be94310 100644
--- a/icu4c/source/test/testdata/break_rules/line_loose_cj.txt
+++ b/icu4c/source/test/testdata/break_rules/line_loose_cj.txt
@@ -38,7 +38,10 @@ locale = ja@lb=loose;
 
 
 AI = [:LineBreak =  Ambiguous:];
+AK = [:LineBreak =  Aksara:];
 AL = [:LineBreak =  Alphabetic:];
+AP = [:LineBreak =  Aksara_Prebase:];
+AS = [:LineBreak =  Aksara_Start:];
 BAX = [\u2010 \u2013];
 BA = [[:LineBreak =  Break_After:] - BAX];
 HH = [\u2010];      # \u2010 is HYPHEN, default line break is BA.
@@ -82,6 +85,8 @@ SA = [:LineBreak =  Complex_Context:];
 SG = [:LineBreak =  Surrogate:];
 SP = [:LineBreak =  Space:];
 SY = [:LineBreak =  Break_Symbols:];
+VF = [:LineBreak =  Virama_Final:];
+VI = [:LineBreak =  Virama:];
 WJ = [:LineBreak =  Word_Joiner:];
 XX = [:LineBreak =  Unknown:];
 ZW = [:LineBreak =  ZWSpace:];
@@ -94,6 +99,9 @@ ZWJ = [:LineBreak =  ZWJ:];
 OP30 = [OP - [\p{ea=F}\p{ea=W}\p{ea=H}]];
 CP30 = [CP - [\p{ea=F}\p{ea=W}\p{ea=H}]];
 
+PiQU = [\p{Pi}&QU];
+PfQU = [\p{Pf}&QU];
+
 # The redundant-looking inner brackets are required for the current parser in the test code.
 ExtPictUnassigned = [[\p{Extended_Pictographic}]&[\p{Cn}]];
 
@@ -126,19 +134,27 @@ LB8:        ZW SP* ÷ [^ZW SP BK CR LF NL];
 LB25:        ((PR | PO | POX)CM*)? ((OP | HY)CM*)? (IS CM*)? NU (CM*(NU | SY | IS))* (CM*(CL | CP))? (CM*(PR | PRX | PO))?;
 
 # Rules LB14 - LB17.
+
+# Moved before LB14, because it matches a supersequence.
+LB15a.1:       ( OP CM* SP* | QU CM* | GL CM* ) (PiQU CM* SP*)+ .;
+
 # Moved up, before LB7, because they can match a longer sequence that would also match LB7.
 # For example, the sequence "OP CM SP AL" matches LB14
 # while the prefix of it, "OP CM SP" matches LB7.1
 LB14:        OP CM* SP* .;
 
-# LB 14a Break before an IS that begins a number and follows a space.
-LB14a:       SP ÷ IS CM* NU;
+LB15a.2:       ^ (PiQU CM* SP*)+ .;
+# LB15b/LB15a chaining.
+LB15b.1:       ([^SP] CM* | SP) PfQU CM* (PiQU CM* SP*)+ .;
+LB15b.2:       ([^SP] CM* | SP) PfQU CM* ( SP | GL | WJ | CL | QU | CP | EX | IS | SY | BK | CR | LF | NL | ZW | $ );
 
-# LB14b       × IS
-LB14b.1:     [^SP] CM* IS;
-LB14b.2:     SP IS;
+# LB 15c Break before an IS that begins a number and follows a space.
+LB15c:       SP ÷ IS CM* NU;
+
+# LB15d       × IS
+LB15d.1:     [^SP] CM* IS;
+LB15d.2:     SP IS;
 
-LB15:        QU CM* SP* OP;
 LB16:        (CL | CP)CM* SP* NS;
 LB17:        B2 CM* SP* B2;
 
@@ -231,6 +247,8 @@ LB27.2:      PR CM* (JL | JV | JT | H2 | H3);
 #      Unattached (leading) CM treated as AL.
 LB28:        (AL | HL | CM)CM* (AL | HL);
 
+LB28: (AP CM*)? (AS | AK | [◌] ) (CM* VI CM* (AK | [◌] ))* (CM* VI | ((CM* (AS | AK | [◌] ) )? CM* VF))?;
+
 LB29:        IS CM* (AL | HL);
 
 # LB30  is adjusted for unattached leading CM being treated as AL.
diff --git a/icu4c/source/test/testdata/break_rules/line_normal.txt b/icu4c/source/test/testdata/break_rules/line_normal.txt
index c718cc2f44c1..0397ec5a5f2b 100644
--- a/icu4c/source/test/testdata/break_rules/line_normal.txt
+++ b/icu4c/source/test/testdata/break_rules/line_normal.txt
@@ -26,7 +26,10 @@ type = line;
 locale = en@lb=normal;
 
 AI = [:LineBreak =  Ambiguous:];
+AK = [:LineBreak =  Aksara:];
 AL = [:LineBreak =  Alphabetic:];
+AP = [:LineBreak =  Aksara_Prebase:];
+AS = [:LineBreak =  Aksara_Start:];
 BA = [:LineBreak =  Break_After:];
 HH = [\u2010];      # \u2010 is HYPHEN, default line break is BA.
 BB = [:LineBreak =  Break_Before:];
@@ -65,6 +68,8 @@ SA = [:LineBreak =  Complex_Context:];
 SG = [:LineBreak =  Surrogate:];
 SP = [:LineBreak =  Space:];
 SY = [:LineBreak =  Break_Symbols:];
+VF = [:LineBreak =  Virama_Final:];
+VI = [:LineBreak =  Virama:];
 WJ = [:LineBreak =  Word_Joiner:];
 XX = [:LineBreak =  Unknown:];
 ZW = [:LineBreak =  ZWSpace:];
@@ -77,6 +82,9 @@ ZWJ = [:LineBreak =  ZWJ:];
 OP30 = [OP - [\p{ea=F}\p{ea=W}\p{ea=H}]];
 CP30 = [CP - [\p{ea=F}\p{ea=W}\p{ea=H}]];
 
+PiQU = [\p{Pi}&QU];
+PfQU = [\p{Pf}&QU];
+
 # The redundant-looking inner brackets are required for the current parser in the test code.
 ExtPictUnassigned = [[\p{Extended_Pictographic}]&[\p{Cn}]];
 
@@ -108,19 +116,27 @@ LB8:        ZW SP* ÷ [^ZW SP BK CR LF NL];
 LB25:        ((PR | PO)CM*)? ((OP | HY)CM*)? (IS CM*)? NU (CM*(NU | SY | IS))* (CM*(CL | CP))? (CM*(PR | PO))?;
 
 # Rules LB14 - LB17.
+
+# Moved before LB14, because it matches a supersequence.
+LB15a.1:       ( OP CM* SP* | QU CM* | GL CM* ) (PiQU CM* SP*)+ .;
+
 # Moved up, before LB7, because they can match a longer sequence that would also match LB7.
 # For example, the sequence "OP CM SP AL" matches LB14
 # while the prefix of it, "OP CM SP" matches LB7.1
 LB14:        OP CM* SP* .;
 
-# LB 14a Break before an IS that begins a number and follows a space.
-LB14a:       SP ÷ IS CM* NU;
+LB15a.2:       ^ (PiQU CM* SP*)+ .;
+# LB15b/LB15a chaining.
+LB15b.1:       ([^SP] CM* | SP) PfQU CM* (PiQU CM* SP*)+ .;
+LB15b.2:       ([^SP] CM* | SP) PfQU CM* ( SP | GL | WJ | CL | QU | CP | EX | IS | SY | BK | CR | LF | NL | ZW | $ );
 
-# LB14b       × IS
-LB14b.1:     [^SP] CM* IS;
-LB14b.2:     SP IS;
+# LB 15c Break before an IS that begins a number and follows a space.
+LB15c:       SP ÷ IS CM* NU;
+
+# LB15d       × IS
+LB15d.1:     [^SP] CM* IS;
+LB15d.2:     SP IS;
 
-LB15:        QU CM* SP* OP;
 LB16:        (CL | CP)CM* SP* NS;
 LB17:        B2 CM* SP* B2;
 
@@ -207,6 +223,8 @@ LB27.2:      PR CM* (JL | JV | JT | H2 | H3);
 #      Unattached (leading) CM treated as AL.
 LB28:        (AL | HL | CM)CM* (AL | HL);
 
+LB28: (AP CM*)? (AS | AK | [◌] ) (CM* VI CM* (AK | [◌] ))* (CM* VI | ((CM* (AS | AK | [◌] ) )? CM* VF))?;
+
 LB29:        IS CM* (AL | HL);
 
 # LB30  is adjusted for unattached leading CM being treated as AL.
diff --git a/icu4c/source/test/testdata/break_rules/line_normal_cj.txt b/icu4c/source/test/testdata/break_rules/line_normal_cj.txt
index a4e1428c2b2e..04889a31ca4e 100644
--- a/icu4c/source/test/testdata/break_rules/line_normal_cj.txt
+++ b/icu4c/source/test/testdata/break_rules/line_normal_cj.txt
@@ -27,7 +27,10 @@ type = line;
 locale = ja@lb=normal;
 
 AI = [:LineBreak =  Ambiguous:];
+AK = [:LineBreak =  Aksara:];
 AL = [:LineBreak =  Alphabetic:];
+AP = [:LineBreak =  Aksara_Prebase:];
+AS = [:LineBreak =  Aksara_Start:];
 BA = [:LineBreak =  Break_After:];
 HH = [\u2010];      # \u2010 is HYPHEN, default line break is BA.
 BB = [:LineBreak =  Break_Before:];
@@ -67,6 +70,8 @@ SA = [:LineBreak =  Complex_Context:];
 SG = [:LineBreak =  Surrogate:];
 SP = [:LineBreak =  Space:];
 SY = [:LineBreak =  Break_Symbols:];
+VF = [:LineBreak =  Virama_Final:];
+VI = [:LineBreak =  Virama:];
 WJ = [:LineBreak =  Word_Joiner:];
 XX = [:LineBreak =  Unknown:];
 ZW = [:LineBreak =  ZWSpace:];
@@ -79,6 +84,9 @@ ZWJ = [:LineBreak =  ZWJ:];
 OP30 = [OP - [\p{ea=F}\p{ea=W}\p{ea=H}]];
 CP30 = [CP - [\p{ea=F}\p{ea=W}\p{ea=H}]];
 
+PiQU = [\p{Pi}&QU];
+PfQU = [\p{Pf}&QU];
+
 # The redundant-looking inner brackets are required for the current parser in the test code.
 ExtPictUnassigned = [[\p{Extended_Pictographic}]&[\p{Cn}]];
 
@@ -110,19 +118,27 @@ LB8:        ZW SP* ÷ [^ZW SP BK CR LF NL];
 LB25:        ((PR | PO)CM*)? ((OP | HY)CM*)? (IS CM*)? NU (CM*(NU | SY | IS))* (CM*(CL | CP))? (CM*(PR | PO))?;
 
 # Rules LB14 - LB17.
+
+# Moved before LB14, because it matches a supersequence.
+LB15a.1:       ( OP CM* SP* | QU CM* | GL CM* ) (PiQU CM* SP*)+ .;
+
 # Moved up, before LB7, because they can match a longer sequence that would also match LB7.
 # For example, the sequence "OP CM SP AL" matches LB14
 # while the prefix of it, "OP CM SP" matches LB7.1
 LB14:        OP CM* SP* .;
 
-# LB 14a Break before an IS that begins a number and follows a space.
-LB14a:       SP ÷ IS CM* NU;
+LB15a.2:       ^ (PiQU CM* SP*)+ .;
+# LB15b/LB15a chaining.
+LB15b.1:       ([^SP] CM* | SP) PfQU CM* (PiQU CM* SP*)+ .;
+LB15b.2:       ([^SP] CM* | SP) PfQU CM* ( SP | GL | WJ | CL | QU | CP | EX | IS | SY | BK | CR | LF | NL | ZW | $ );
 
-# LB14b       × IS
-LB14b.1:     [^SP] CM* IS;
-LB14b.2:     SP IS;
+# LB 15c Break before an IS that begins a number and follows a space.
+LB15c:       SP ÷ IS CM* NU;
+
+# LB15d       × IS
+LB15d.1:     [^SP] CM* IS;
+LB15d.2:     SP IS;
 
-LB15:        QU CM* SP* OP;
 
 # Do not break between closing punctuation and $NS, even with intervening spaces
 # But DO allow a break between closing punctuation and $NSX, don't include it here
@@ -211,6 +227,8 @@ LB27.2:      PR CM* (JL | JV | JT | H2 | H3);
 #      Unattached (leading) CM treated as AL.
 LB28:        (AL | HL | CM)CM* (AL | HL);
 
+LB28: (AP CM*)? (AS | AK | [◌] ) (CM* VI CM* (AK | [◌] ))* (CM* VI | ((CM* (AS | AK | [◌] ) )? CM* VF))?;
+
 LB29:        IS CM* (AL | HL);
 
 # LB30  is adjusted for unattached leading CM being treated as AL.
diff --git a/icu4c/source/test/testdata/rbbitst.txt b/icu4c/source/test/testdata/rbbitst.txt
index 175ec7966411..772acf24363c 100644
--- a/icu4c/source/test/testdata/rbbitst.txt
+++ b/icu4c/source/test/testdata/rbbitst.txt
@@ -2206,3 +2206,13 @@ Bangkok)•</data>
 <data>•\U00011F26•\U00011F02\U00011F2D•\U00011F26\U00011F42\U00011F26•\U00011F31\U00011F41•</data>
 <data>•\u1BD7\u1BEC•\u1BD2\u1BEA\u1BC9\u1BF3•\u1BC2\u1BE7\u1BC9\u1BF3•</data>
 <data>•\u1B18•\u1B27\u1B44\u200C\u1B2B\u1B38•\u1B31\u1B44\u1B1D\u1B36•</data>
+
+# Line breaking around quotation marks (LB 15a and LB 15b).
+<locale en>
+<line>
+<data>•Some •« basic » •quoting•</data>
+<data>•Some •»German« •quoting•</data>
+<data>•( « bracketed » ) •quoting•</data>
+<data>•« « Nesting » »•</data>
+<data>•« Complex »« chaining » •</data>
+<data>•« .618 »•</data>  # Interaction with the ICU tailoring to break before such numbers.
\ No newline at end of file
diff --git a/icu4j/main/shared/data/icudata.jar b/icu4j/main/shared/data/icudata.jar
index cd832e89e145..de8c54a72393 100644
--- a/icu4j/main/shared/data/icudata.jar
+++ b/icu4j/main/shared/data/icudata.jar
@@ -1,3 +1,3 @@
 version https://git-lfs.github.com/spec/v1
-oid sha256:43e6290edfaef19328dfa54c5fc301b36c57489cec9658c5eeb13a186e8eaad7
-size 14340466
+oid sha256:c1952ee8136d59a785d51caf70e7f56ca477ed036e83465bafddf3ed8c86e5b5
+size 14351596
diff --git a/icu4j/main/shared/data/icutzdata.jar b/icu4j/main/shared/data/icutzdata.jar
index 1ecdf571e51a..f585f17a6fa1 100644
--- a/icu4j/main/shared/data/icutzdata.jar
+++ b/icu4j/main/shared/data/icutzdata.jar
@@ -1,3 +1,3 @@
 version https://git-lfs.github.com/spec/v1
-oid sha256:9d0821499d99b54fa4bb80a5aaca12cd07cc71aea8a372e7c273691891973cb9
-size 94829
+oid sha256:cbdbc0dabb200a00781ef7423cf2ad5a8fd341e1b47897477bfd64dc03537731
+size 94837
diff --git a/icu4j/main/shared/data/testdata.jar b/icu4j/main/shared/data/testdata.jar
index 22664d934c8d..41facb5f388e 100644
--- a/icu4j/main/shared/data/testdata.jar
+++ b/icu4j/main/shared/data/testdata.jar
@@ -1,3 +1,3 @@
 version https://git-lfs.github.com/spec/v1
-oid sha256:f8bd64e37315224765b48d7a527aacbff04c3a1227d2378e7c822e5e1a49b568
-size 831983
+oid sha256:ffc267e9bd1a9c95cbaf261de6c50856ba8d848d7198f18458d06b82e8536c7b
+size 834969
diff --git a/icu4j/main/tests/core/src/com/ibm/icu/dev/test/rbbi/RBBITestMonkey.java b/icu4j/main/tests/core/src/com/ibm/icu/dev/test/rbbi/RBBITestMonkey.java
index 7a30389d4679..ce45e1c13997 100644
--- a/icu4j/main/tests/core/src/com/ibm/icu/dev/test/rbbi/RBBITestMonkey.java
+++ b/icu4j/main/tests/core/src/com/ibm/icu/dev/test/rbbi/RBBITestMonkey.java
@@ -748,6 +748,13 @@ public boolean contains(int codePoint) {
         XUnicodeSet fOP30;
         XUnicodeSet fCP30;
         XUnicodeSet fExtPictUnassigned;
+        XUnicodeSet fAK;
+        XUnicodeSet fAP;
+        XUnicodeSet fAS;
+        XUnicodeSet fVF;
+        XUnicodeSet fVI;
+        XUnicodeSet fPi;
+        XUnicodeSet fPf;
 
         StringBuffer  fText;
         int           fOrigPositions;
@@ -802,6 +809,14 @@ public boolean contains(int codePoint) {
             fOP30  = new XUnicodeSet("[\\p{Line_break=OP}-[\\p{ea=F}\\p{ea=W}\\p{ea=H}]]");
             fCP30  = new XUnicodeSet("[\\p{Line_break=CP}-[\\p{ea=F}\\p{ea=W}\\p{ea=H}]]");
             fExtPictUnassigned = new XUnicodeSet("[\\p{Extended_Pictographic}&\\p{Cn}]");
+            fAK = new XUnicodeSet("[\\p{Line_Break=AK}]");
+            fAP = new XUnicodeSet("[\\p{Line_Break=AP}]");
+            fAS = new XUnicodeSet("[\\p{Line_Break=AS}]");
+            fVF = new XUnicodeSet("[\\p{Line_Break=VF}]");
+            fVI = new XUnicodeSet("[\\p{Line_Break=VI}]");
+
+            fPi = new XUnicodeSet("[\\p{Pi}]");
+            fPf = new XUnicodeSet("[\\p{Pf}]");
 
             // Remove dictionary characters.
             // The monkey test reference implementation of line break does not replicate the dictionary behavior,
@@ -863,6 +878,11 @@ public boolean contains(int codePoint) {
             fSets.add(fOP30);   fClassNames.add("OP30");
             fSets.add(fCP30);   fClassNames.add("CP30");
             fSets.add(fExtPictUnassigned); fClassNames.add("fExtPictUnassigned");
+            fSets.add(fAK); fClassNames.add("AK");
+            fSets.add(fAP); fClassNames.add("AP");
+            fSets.add(fAS); fClassNames.add("AS");
+            fSets.add(fVF); fClassNames.add("VF");
+            fSets.add(fVI); fClassNames.add("VI");
         }
 
         @Override
@@ -1095,34 +1115,69 @@ int next(int startPos) {
                     continue;
                 }
 
-                if (nextPos < fText.length()) {
-                    int nextChar = fText.codePointAt(nextPos);
-                    if (fSP.contains(prevChar) && fIS.contains(thisChar) && fNU.contains(nextChar)) {
-                        setAppliedRule(pos, "LB 14a Break before an IS that begins a number and follows a space");
-                        break;
+                // Same as LB 14, scan backward for
+                // (sot | BK | CR | LF | NL | OP CM*| QU CM* | GL CM* | SP) [\p{Pi}&QU] CM* SP*.
+                tPos = prevPos;
+                // SP* (with the aforementioned Twist).
+                if (fSP.contains(prevChar)) {
+                    while (tPos > 0 && fSP.contains(UTF16.charAt(fText, tPos))) {
+                        tPos = moveIndex32(fText, tPos, -1);
                     }
                 }
-
-                if (fIS.contains(thisChar)) {
-                    setAppliedRule(pos, "LB 14b Do not break before numeric separators, even after spaces");
-                    continue;
+                // CM*.
+                while (tPos > 0 && fCM.contains(UTF16.charAt(fText, tPos))) {
+                    tPos = moveIndex32(fText, tPos, -1);
                 }
-
-                if (fOP.contains(thisChar)) {
-                    // Scan backwards from prevChar to see if it is preceded by QU CM* SP*
-                    tPos = prevPos;
-                    while (tPos > 0 && fSP.contains(UTF16.charAt(fText, tPos))) {
+                // [\p{Pi}&QU].
+                if (fPi.contains(UTF16.charAt(fText, tPos)) && fQU.contains(UTF16.charAt(fText, tPos))) {
+                    if (tPos == 0) {
+                        setAppliedRule(pos, "LB 15a sot [\\p{Pi}&QU] SP* ×");
+                        continue;
+                    } else {
                         tPos = moveIndex32(fText, tPos, -1);
+                        if (fBK.contains(UTF16.charAt(fText, tPos)) || fCR.contains(UTF16.charAt(fText, tPos)) ||
+                            fLF.contains(UTF16.charAt(fText, tPos)) || fNL.contains(UTF16.charAt(fText, tPos)) ||
+                            fSP.contains(UTF16.charAt(fText, tPos)) || fZW.contains(UTF16.charAt(fText, tPos))) {
+                            setAppliedRule(pos, "LB 15a (BK | CR | LF | NL | SP | ZW) [\\p{Pi}&QU] SP* ×");
+                            continue;
+                        }
                     }
+                    // CM*.
                     while (tPos > 0 && fCM.contains(UTF16.charAt(fText, tPos))) {
                         tPos = moveIndex32(fText, tPos, -1);
                     }
-                    if (fQU.contains(UTF16.charAt(fText, tPos))) {
-                        setAppliedRule(pos, "LB 15  QU SP* x OP");
+                    if (fOP.contains(UTF16.charAt(fText, tPos)) || fQU.contains(UTF16.charAt(fText, tPos)) ||
+                        fGL.contains(UTF16.charAt(fText, tPos))) {
+                        setAppliedRule(pos, "LB 15a (OP | QU | GL) [\\p{Pi}&QU] SP* ×");
+                        continue;
+                    }
+                }
+
+                if (fPf.contains(thisChar) && fQU.contains(thisChar)) {
+                    int nextChar = UTF16.charAt(fText, nextPos);
+                    if (nextPos == fText.length() || fSP.contains(nextChar) || fGL.contains(nextChar) ||
+                        fWJ.contains(nextChar) || fCL.contains(nextChar) || fQU.contains(nextChar) ||
+                        fCP.contains(nextChar) || fEX.contains(nextChar) || fIS.contains(nextChar) ||
+                        fSY.contains(nextChar) || fBK.contains(nextChar) || fCR.contains(nextChar) ||
+                        fLF.contains(nextChar) || fNL.contains(nextChar) || fZW.contains(nextChar)) {
+                        setAppliedRule(pos, "LB 15b × [\\p{Pf}&QU] ( SP | GL | WJ | CL | QU | CP | EX | IS | SY | BK | CR | LF | NL | ZW | eot)");
                         continue;
                     }
                 }
 
+                if (nextPos < fText.length()) {
+                    int nextChar = fText.codePointAt(nextPos);
+                    if (fSP.contains(prevChar) && fIS.contains(thisChar) && fNU.contains(nextChar)) {
+                        setAppliedRule(pos, "LB 15c Break before an IS that begins a number and follows a space");
+                        break;
+                    }
+                }
+
+                if (fIS.contains(thisChar)) {
+                    setAppliedRule(pos, "LB 15d Do not break before numeric separators, even after spaces");
+                    continue;
+                }
+
                 if (fNS.contains(thisChar)) {
                     tPos = prevPos;
                     while (tPos > 0 && fSP.contains(UTF16.charAt(fText, tPos))) {
@@ -1282,6 +1337,37 @@ int next(int startPos) {
                     continue;
                 }
 
+                if (fAP.contains(prevChar) &&
+                    (fAK.contains(thisChar) || thisChar == '◌' || fAS.contains(thisChar))) {
+                    setAppliedRule(pos, "LB 28a.1  AP x (AK | ◌ | AS)");
+                    continue;
+                }
+        
+                if ((fAK.contains(prevChar) || prevChar == '◌' || fAS.contains(prevChar)) &&
+                    (fVF.contains(thisChar) || fVI.contains(thisChar))) {
+                    setAppliedRule(pos, "LB 28a.2  (AK | ◌ | AS) x (VF | VI)");
+                    continue;
+                }
+        
+                if ((fAK.contains(prevCharX2) || prevCharX2 == '◌' || fAS.contains(prevCharX2)) &&
+                    fVI.contains(prevChar) &&
+                    (fAK.contains(thisChar) || thisChar == '◌')) {
+                    setAppliedRule(pos, "LB 28a.3  (AK | ◌ | AS) VI x (AK | ◌)");
+                    continue;
+                }
+        
+                if (nextPos < fText.length()) {
+                    // note: UnicodeString::char32At(length) returns ffff, not distinguishable
+                    //       from a legit ffff noncharacter. So test length separately.
+                    int nextChar = UTF16.charAt(fText, nextPos);
+                    if ((fAK.contains(prevChar) || prevChar == '◌' || fAS.contains(prevChar)) &&
+                        (fAK.contains(thisChar) || thisChar == '◌' || fAS.contains(thisChar)) &&
+                        fVF.contains(nextChar)) {
+                        setAppliedRule(pos, "LB 28a.4  (AK | ◌ | AS) x (AK | ◌ | AS) VF");
+                        continue;
+                    }
+                }
+
                 if (fIS.contains(prevChar) && (fAL.contains(thisChar) || fHL.contains(thisChar))) {
                     setAppliedRule(pos, "LB 29  Do not break between numeric punctuation and alphabetics");
                     continue;
diff --git a/icu4j/main/tests/core/src/com/ibm/icu/dev/test/rbbi/break_rules/line.txt b/icu4j/main/tests/core/src/com/ibm/icu/dev/test/rbbi/break_rules/line.txt
index 409f223ed6f4..c68a66b95f20 100644
--- a/icu4j/main/tests/core/src/com/ibm/icu/dev/test/rbbi/break_rules/line.txt
+++ b/icu4j/main/tests/core/src/com/ibm/icu/dev/test/rbbi/break_rules/line.txt
@@ -24,7 +24,10 @@ locale = en;
 
 
 AI = [:LineBreak =  Ambiguous:];
+AK = [:LineBreak =  Aksara:];
 AL = [:LineBreak =  Alphabetic:];
+AP = [:LineBreak =  Aksara_Prebase:];
+AS = [:LineBreak =  Aksara_Start:];
 BA = [:LineBreak =  Break_After:];
 HH = [\u2010];      # \u2010 is HYPHEN, default line break is BA.
 BB = [:LineBreak =  Break_Before:];
@@ -63,6 +66,8 @@ SA = [:LineBreak =  Complex_Context:];
 SG = [:LineBreak =  Surrogate:];
 SP = [:LineBreak =  Space:];
 SY = [:LineBreak =  Break_Symbols:];
+VF = [:LineBreak =  Virama_Final:];
+VI = [:LineBreak =  Virama:];
 WJ = [:LineBreak =  Word_Joiner:];
 XX = [:LineBreak =  Unknown:];
 ZW = [:LineBreak =  ZWSpace:];
@@ -75,6 +80,9 @@ ZWJ = [:LineBreak =  ZWJ:];
 OP30 = [OP - [\p{ea=F}\p{ea=W}\p{ea=H}]];
 CP30 = [CP - [\p{ea=F}\p{ea=W}\p{ea=H}]];
 
+PiQU = [\p{Pi}&QU];
+PfQU = [\p{Pf}&QU];
+
 # The redundant-looking inner brackets are required for the current parser in the test code.
 ExtPictUnassigned = [[\p{Extended_Pictographic}]&[\p{Cn}]];
 
@@ -106,19 +114,27 @@ LB8:        ZW SP* ÷ [^ZW SP BK CR LF NL];
 LB25:        ((PR | PO)CM*)? ((OP | HY)CM*)? (IS CM*)? NU (CM*(NU | SY | IS))* (CM*(CL | CP))? (CM*(PR | PO))?;
 
 # Rules LB14 - LB17.
+
+# Moved before LB14, because it matches a supersequence.
+LB15a.1:       ( OP CM* SP* | QU CM* | GL CM* ) (PiQU CM* SP*)+ .;
+
 # Moved up, before LB7, because they can match a longer sequence that would also match LB7.
 # For example, the sequence "OP CM SP AL" matches LB14
 # while the prefix of it, "OP CM SP" matches LB7.1
 LB14:        OP CM* SP* .;
 
-# LB 14a Break before an IS that begins a number and follows a space.
-LB14a:       SP ÷ IS CM* NU;
+LB15a.2:       ^ (PiQU CM* SP*)+ .;
+# LB15b/LB15a chaining.
+LB15b.1:       ([^SP] CM* | SP) PfQU CM* (PiQU CM* SP*)+ .;
+LB15b.2:       ([^SP] CM* | SP) PfQU CM* ( SP | GL | WJ | CL | QU | CP | EX | IS | SY | BK | CR | LF | NL | ZW | $ );
 
-# LB14b       × IS
-LB14b.1:     [^SP] CM* IS;
-LB14b.2:     SP IS;
+# LB 15c Break before an IS that begins a number and follows a space.
+LB15c:       SP ÷ IS CM* NU;
+
+# LB15d       × IS
+LB15d.1:     [^SP] CM* IS;
+LB15d.2:     SP IS;
 
-LB15:        QU CM* SP* OP;
 LB16:        (CL | CP)CM* SP* NS;
 LB17:        B2 CM* SP* B2;
 
@@ -205,6 +221,8 @@ LB27.2:      PR CM* (JL | JV | JT | H2 | H3);
 #      Unattached (leading) CM treated as AL.
 LB28:        (AL | HL | CM)CM* (AL | HL);
 
+LB28: (AP CM*)? (AS | AK | [◌] ) (CM* VI CM* (AK | [◌] ))* (CM* VI | ((CM* (AS | AK | [◌] ) )? CM* VF))?;
+
 LB29:        IS CM* (AL | HL);
 
 # LB30  is adjusted for unattached leading CM being treated as AL.
diff --git a/icu4j/main/tests/core/src/com/ibm/icu/dev/test/rbbi/break_rules/line_cj.txt b/icu4j/main/tests/core/src/com/ibm/icu/dev/test/rbbi/break_rules/line_cj.txt
index e66b0d134ada..bcfc94f05485 100644
--- a/icu4j/main/tests/core/src/com/ibm/icu/dev/test/rbbi/break_rules/line_cj.txt
+++ b/icu4j/main/tests/core/src/com/ibm/icu/dev/test/rbbi/break_rules/line_cj.txt
@@ -17,7 +17,10 @@ locale = zh;
 
 
 AI = [:LineBreak =  Ambiguous:];
+AK = [:LineBreak =  Aksara:];
 AL = [:LineBreak =  Alphabetic:];
+AP = [:LineBreak =  Aksara_Prebase:];
+AS = [:LineBreak =  Aksara_Start:];
 BA = [:LineBreak =  Break_After:];
 HH = [\u2010];      # \u2010 is HYPHEN, default line break is BA.
 BB = [:LineBreak =  Break_Before:];
@@ -56,6 +59,8 @@ SA = [:LineBreak =  Complex_Context:];
 SG = [:LineBreak =  Surrogate:];
 SP = [:LineBreak =  Space:];
 SY = [:LineBreak =  Break_Symbols:];
+VF = [:LineBreak =  Virama_Final:];
+VI = [:LineBreak =  Virama:];
 WJ = [:LineBreak =  Word_Joiner:];
 XX = [:LineBreak =  Unknown:];
 ZW = [:LineBreak =  ZWSpace:];
@@ -75,6 +80,9 @@ CP30 = [CP - [\p{ea=F}\p{ea=W}\p{ea=H}]];
 OP30 = [OP - [\p{ea=F}\p{ea=W}\p{ea=H}]];
 CP30 = [CP - [\p{ea=F}\p{ea=W}\p{ea=H}]];
 
+PiQU = [\p{Pi}&QU];
+PfQU = [\p{Pf}&QU];
+
 # The redundant-looking inner brackets are required for the current parser in the test code.
 ExtPictUnassigned = [[\p{Extended_Pictographic}]&[\p{Cn}]];
 
@@ -106,19 +114,27 @@ LB8:        ZW SP* ÷ [^ZW SP BK CR LF NL];
 LB25:        ((PR | PO)CM*)? ((OP | HY)CM*)? (IS CM*)? NU (CM*(NU | SY | IS))* (CM*(CL | CP))? (CM*(PR | PO))?;
 
 # Rules LB14 - LB17.
+
+# Moved before LB14, because it matches a supersequence.
+LB15a.1:       ( OP CM* SP* | QU CM* | GL CM* ) (PiQU CM* SP*)+ .;
+
 # Moved up, before LB7, because they can match a longer sequence that would also match LB7.
 # For example, the sequence "OP CM SP AL" matches LB14
 # while the prefix of it, "OP CM SP" matches LB7.1
 LB14:        OP CM* SP* .;
 
-# LB 14a Break before an IS that begins a number and follows a space.
-LB14a:       SP ÷ IS CM* NU;
+LB15a.2:       ^ (PiQU CM* SP*)+ .;
+# LB15b/LB15a chaining.
+LB15b.1:       ([^SP] CM* | SP) PfQU CM* (PiQU CM* SP*)+ .;
+LB15b.2:       ([^SP] CM* | SP) PfQU CM* ( SP | GL | WJ | CL | QU | CP | EX | IS | SY | BK | CR | LF | NL | ZW | $ );
 
-# LB14b       × IS
-LB14b.1:     [^SP] CM* IS;
-LB14b.2:     SP IS;
+# LB 15c Break before an IS that begins a number and follows a space.
+LB15c:       SP ÷ IS CM* NU;
+
+# LB15d       × IS
+LB15d.1:     [^SP] CM* IS;
+LB15d.2:     SP IS;
 
-LB15:        QU CM* SP* OP;
 LB16:        (CL | CP)CM* SP* NS;
 LB17:        B2 CM* SP* B2;
 
@@ -205,6 +221,8 @@ LB27.2:      PR CM* (JL | JV | JT | H2 | H3);
 #      Unattached (leading) CM treated as AL.
 LB28:        (AL | HL | CM)CM* (AL | HL);
 
+LB28: (AP CM*)? (AS | AK | [◌] ) (CM* VI CM* (AK | [◌] ))* (CM* VI | ((CM* (AS | AK | [◌] ) )? CM* VF))?;
+
 LB29:        IS CM* (AL | HL);
 
 # LB30  is adjusted for unattached leading CM being treated as AL.
diff --git a/icu4j/main/tests/core/src/com/ibm/icu/dev/test/rbbi/break_rules/line_loose.txt b/icu4j/main/tests/core/src/com/ibm/icu/dev/test/rbbi/break_rules/line_loose.txt
index 54873a489698..05c2bea74025 100644
--- a/icu4j/main/tests/core/src/com/ibm/icu/dev/test/rbbi/break_rules/line_loose.txt
+++ b/icu4j/main/tests/core/src/com/ibm/icu/dev/test/rbbi/break_rules/line_loose.txt
@@ -24,7 +24,10 @@ locale = en@lb=loose;
 
 
 AI = [:LineBreak =  Ambiguous:];
+AK = [:LineBreak =  Aksara:];
 AL = [:LineBreak =  Alphabetic:];
+AP = [:LineBreak =  Aksara_Prebase:];
+AS = [:LineBreak =  Aksara_Start:];
 BA = [:LineBreak =  Break_After:];
 HH = [\u2010];      # \u2010 is HYPHEN, default line break is BA.
 BB = [:LineBreak =  Break_Before:];
@@ -64,6 +67,8 @@ SA = [:LineBreak =  Complex_Context:];
 SG = [:LineBreak =  Surrogate:];
 SP = [:LineBreak =  Space:];
 SY = [:LineBreak =  Break_Symbols:];
+VF = [:LineBreak =  Virama_Final:];
+VI = [:LineBreak =  Virama:];
 WJ = [:LineBreak =  Word_Joiner:];
 XX = [:LineBreak =  Unknown:];
 ZW = [:LineBreak =  ZWSpace:];
@@ -76,6 +81,9 @@ ZWJ = [:LineBreak =  ZWJ:];
 OP30 = [OP - [\p{ea=F}\p{ea=W}\p{ea=H}]];
 CP30 = [CP - [\p{ea=F}\p{ea=W}\p{ea=H}]];
 
+PiQU = [\p{Pi}&QU];
+PfQU = [\p{Pf}&QU];
+
 # The redundant-looking inner brackets are required for the current parser in the test code.
 ExtPictUnassigned = [[\p{Extended_Pictographic}]&[\p{Cn}]];
 
@@ -107,19 +115,27 @@ LB8:        ZW SP* ÷ [^ZW SP BK CR LF NL];
 LB25:        ((PR | PO)CM*)? ((OP | HY)CM*)? (IS CM*)? NU (CM*(NU | SY | IS))* (CM*(CL | CP))? (CM*(PR | PO))?;
 
 # Rules LB14 - LB17.
+
+# Moved before LB14, because it matches a supersequence.
+LB15a.1:       ( OP CM* SP* | QU CM* | GL CM* ) (PiQU CM* SP*)+ .;
+
 # Moved up, before LB7, because they can match a longer sequence that would also match LB7.
 # For example, the sequence "OP CM SP AL" matches LB14
 # while the prefix of it, "OP CM SP" matches LB7.1
 LB14:        OP CM* SP* .;
 
-# LB 14a Break before an IS that begins a number and follows a space.
-LB14a:       SP ÷ IS CM* NU;
+LB15a.2:       ^ (PiQU CM* SP*)+ .;
+# LB15b/LB15a chaining.
+LB15b.1:       ([^SP] CM* | SP) PfQU CM* (PiQU CM* SP*)+ .;
+LB15b.2:       ([^SP] CM* | SP) PfQU CM* ( SP | GL | WJ | CL | QU | CP | EX | IS | SY | BK | CR | LF | NL | ZW | $ );
 
-# LB14b       × IS
-LB14b.1:     [^SP] CM* IS;
-LB14b.2:     SP IS;
+# LB 15c Break before an IS that begins a number and follows a space.
+LB15c:       SP ÷ IS CM* NU;
+
+# LB15d       × IS
+LB15d.1:     [^SP] CM* IS;
+LB15d.2:     SP IS;
 
-LB15:        QU CM* SP* OP;
 LB16:        (CL | CP)CM* SP* NS;
 LB17:        B2 CM* SP* B2;
 
@@ -207,6 +223,8 @@ LB27.2:      PR CM* (JL | JV | JT | H2 | H3);
 #      Unattached (leading) CM treated as AL.
 LB28:        (AL | HL | CM)CM* (AL | HL);
 
+LB28: (AP CM*)? (AS | AK | [◌] ) (CM* VI CM* (AK | [◌] ))* (CM* VI | ((CM* (AS | AK | [◌] ) )? CM* VF))?;
+
 LB29:        IS CM* (AL | HL);
 
 # LB30  is adjusted for unattached leading CM being treated as AL.
diff --git a/icu4j/main/tests/core/src/com/ibm/icu/dev/test/rbbi/break_rules/line_loose_cj.txt b/icu4j/main/tests/core/src/com/ibm/icu/dev/test/rbbi/break_rules/line_loose_cj.txt
index 9d7b2cc12c6d..93a06be94310 100644
--- a/icu4j/main/tests/core/src/com/ibm/icu/dev/test/rbbi/break_rules/line_loose_cj.txt
+++ b/icu4j/main/tests/core/src/com/ibm/icu/dev/test/rbbi/break_rules/line_loose_cj.txt
@@ -38,7 +38,10 @@ locale = ja@lb=loose;
 
 
 AI = [:LineBreak =  Ambiguous:];
+AK = [:LineBreak =  Aksara:];
 AL = [:LineBreak =  Alphabetic:];
+AP = [:LineBreak =  Aksara_Prebase:];
+AS = [:LineBreak =  Aksara_Start:];
 BAX = [\u2010 \u2013];
 BA = [[:LineBreak =  Break_After:] - BAX];
 HH = [\u2010];      # \u2010 is HYPHEN, default line break is BA.
@@ -82,6 +85,8 @@ SA = [:LineBreak =  Complex_Context:];
 SG = [:LineBreak =  Surrogate:];
 SP = [:LineBreak =  Space:];
 SY = [:LineBreak =  Break_Symbols:];
+VF = [:LineBreak =  Virama_Final:];
+VI = [:LineBreak =  Virama:];
 WJ = [:LineBreak =  Word_Joiner:];
 XX = [:LineBreak =  Unknown:];
 ZW = [:LineBreak =  ZWSpace:];
@@ -94,6 +99,9 @@ ZWJ = [:LineBreak =  ZWJ:];
 OP30 = [OP - [\p{ea=F}\p{ea=W}\p{ea=H}]];
 CP30 = [CP - [\p{ea=F}\p{ea=W}\p{ea=H}]];
 
+PiQU = [\p{Pi}&QU];
+PfQU = [\p{Pf}&QU];
+
 # The redundant-looking inner brackets are required for the current parser in the test code.
 ExtPictUnassigned = [[\p{Extended_Pictographic}]&[\p{Cn}]];
 
@@ -126,19 +134,27 @@ LB8:        ZW SP* ÷ [^ZW SP BK CR LF NL];
 LB25:        ((PR | PO | POX)CM*)? ((OP | HY)CM*)? (IS CM*)? NU (CM*(NU | SY | IS))* (CM*(CL | CP))? (CM*(PR | PRX | PO))?;
 
 # Rules LB14 - LB17.
+
+# Moved before LB14, because it matches a supersequence.
+LB15a.1:       ( OP CM* SP* | QU CM* | GL CM* ) (PiQU CM* SP*)+ .;
+
 # Moved up, before LB7, because they can match a longer sequence that would also match LB7.
 # For example, the sequence "OP CM SP AL" matches LB14
 # while the prefix of it, "OP CM SP" matches LB7.1
 LB14:        OP CM* SP* .;
 
-# LB 14a Break before an IS that begins a number and follows a space.
-LB14a:       SP ÷ IS CM* NU;
+LB15a.2:       ^ (PiQU CM* SP*)+ .;
+# LB15b/LB15a chaining.
+LB15b.1:       ([^SP] CM* | SP) PfQU CM* (PiQU CM* SP*)+ .;
+LB15b.2:       ([^SP] CM* | SP) PfQU CM* ( SP | GL | WJ | CL | QU | CP | EX | IS | SY | BK | CR | LF | NL | ZW | $ );
 
-# LB14b       × IS
-LB14b.1:     [^SP] CM* IS;
-LB14b.2:     SP IS;
+# LB 15c Break before an IS that begins a number and follows a space.
+LB15c:       SP ÷ IS CM* NU;
+
+# LB15d       × IS
+LB15d.1:     [^SP] CM* IS;
+LB15d.2:     SP IS;
 
-LB15:        QU CM* SP* OP;
 LB16:        (CL | CP)CM* SP* NS;
 LB17:        B2 CM* SP* B2;
 
@@ -231,6 +247,8 @@ LB27.2:      PR CM* (JL | JV | JT | H2 | H3);
 #      Unattached (leading) CM treated as AL.
 LB28:        (AL | HL | CM)CM* (AL | HL);
 
+LB28: (AP CM*)? (AS | AK | [◌] ) (CM* VI CM* (AK | [◌] ))* (CM* VI | ((CM* (AS | AK | [◌] ) )? CM* VF))?;
+
 LB29:        IS CM* (AL | HL);
 
 # LB30  is adjusted for unattached leading CM being treated as AL.
diff --git a/icu4j/main/tests/core/src/com/ibm/icu/dev/test/rbbi/break_rules/line_normal.txt b/icu4j/main/tests/core/src/com/ibm/icu/dev/test/rbbi/break_rules/line_normal.txt
index c718cc2f44c1..0397ec5a5f2b 100644
--- a/icu4j/main/tests/core/src/com/ibm/icu/dev/test/rbbi/break_rules/line_normal.txt
+++ b/icu4j/main/tests/core/src/com/ibm/icu/dev/test/rbbi/break_rules/line_normal.txt
@@ -26,7 +26,10 @@ type = line;
 locale = en@lb=normal;
 
 AI = [:LineBreak =  Ambiguous:];
+AK = [:LineBreak =  Aksara:];
 AL = [:LineBreak =  Alphabetic:];
+AP = [:LineBreak =  Aksara_Prebase:];
+AS = [:LineBreak =  Aksara_Start:];
 BA = [:LineBreak =  Break_After:];
 HH = [\u2010];      # \u2010 is HYPHEN, default line break is BA.
 BB = [:LineBreak =  Break_Before:];
@@ -65,6 +68,8 @@ SA = [:LineBreak =  Complex_Context:];
 SG = [:LineBreak =  Surrogate:];
 SP = [:LineBreak =  Space:];
 SY = [:LineBreak =  Break_Symbols:];
+VF = [:LineBreak =  Virama_Final:];
+VI = [:LineBreak =  Virama:];
 WJ = [:LineBreak =  Word_Joiner:];
 XX = [:LineBreak =  Unknown:];
 ZW = [:LineBreak =  ZWSpace:];
@@ -77,6 +82,9 @@ ZWJ = [:LineBreak =  ZWJ:];
 OP30 = [OP - [\p{ea=F}\p{ea=W}\p{ea=H}]];
 CP30 = [CP - [\p{ea=F}\p{ea=W}\p{ea=H}]];
 
+PiQU = [\p{Pi}&QU];
+PfQU = [\p{Pf}&QU];
+
 # The redundant-looking inner brackets are required for the current parser in the test code.
 ExtPictUnassigned = [[\p{Extended_Pictographic}]&[\p{Cn}]];
 
@@ -108,19 +116,27 @@ LB8:        ZW SP* ÷ [^ZW SP BK CR LF NL];
 LB25:        ((PR | PO)CM*)? ((OP | HY)CM*)? (IS CM*)? NU (CM*(NU | SY | IS))* (CM*(CL | CP))? (CM*(PR | PO))?;
 
 # Rules LB14 - LB17.
+
+# Moved before LB14, because it matches a supersequence.
+LB15a.1:       ( OP CM* SP* | QU CM* | GL CM* ) (PiQU CM* SP*)+ .;
+
 # Moved up, before LB7, because they can match a longer sequence that would also match LB7.
 # For example, the sequence "OP CM SP AL" matches LB14
 # while the prefix of it, "OP CM SP" matches LB7.1
 LB14:        OP CM* SP* .;
 
-# LB 14a Break before an IS that begins a number and follows a space.
-LB14a:       SP ÷ IS CM* NU;
+LB15a.2:       ^ (PiQU CM* SP*)+ .;
+# LB15b/LB15a chaining.
+LB15b.1:       ([^SP] CM* | SP) PfQU CM* (PiQU CM* SP*)+ .;
+LB15b.2:       ([^SP] CM* | SP) PfQU CM* ( SP | GL | WJ | CL | QU | CP | EX | IS | SY | BK | CR | LF | NL | ZW | $ );
 
-# LB14b       × IS
-LB14b.1:     [^SP] CM* IS;
-LB14b.2:     SP IS;
+# LB 15c Break before an IS that begins a number and follows a space.
+LB15c:       SP ÷ IS CM* NU;
+
+# LB15d       × IS
+LB15d.1:     [^SP] CM* IS;
+LB15d.2:     SP IS;
 
-LB15:        QU CM* SP* OP;
 LB16:        (CL | CP)CM* SP* NS;
 LB17:        B2 CM* SP* B2;
 
@@ -207,6 +223,8 @@ LB27.2:      PR CM* (JL | JV | JT | H2 | H3);
 #      Unattached (leading) CM treated as AL.
 LB28:        (AL | HL | CM)CM* (AL | HL);
 
+LB28: (AP CM*)? (AS | AK | [◌] ) (CM* VI CM* (AK | [◌] ))* (CM* VI | ((CM* (AS | AK | [◌] ) )? CM* VF))?;
+
 LB29:        IS CM* (AL | HL);
 
 # LB30  is adjusted for unattached leading CM being treated as AL.
diff --git a/icu4j/main/tests/core/src/com/ibm/icu/dev/test/rbbi/break_rules/line_normal_cj.txt b/icu4j/main/tests/core/src/com/ibm/icu/dev/test/rbbi/break_rules/line_normal_cj.txt
index a4e1428c2b2e..04889a31ca4e 100644
--- a/icu4j/main/tests/core/src/com/ibm/icu/dev/test/rbbi/break_rules/line_normal_cj.txt
+++ b/icu4j/main/tests/core/src/com/ibm/icu/dev/test/rbbi/break_rules/line_normal_cj.txt
@@ -27,7 +27,10 @@ type = line;
 locale = ja@lb=normal;
 
 AI = [:LineBreak =  Ambiguous:];
+AK = [:LineBreak =  Aksara:];
 AL = [:LineBreak =  Alphabetic:];
+AP = [:LineBreak =  Aksara_Prebase:];
+AS = [:LineBreak =  Aksara_Start:];
 BA = [:LineBreak =  Break_After:];
 HH = [\u2010];      # \u2010 is HYPHEN, default line break is BA.
 BB = [:LineBreak =  Break_Before:];
@@ -67,6 +70,8 @@ SA = [:LineBreak =  Complex_Context:];
 SG = [:LineBreak =  Surrogate:];
 SP = [:LineBreak =  Space:];
 SY = [:LineBreak =  Break_Symbols:];
+VF = [:LineBreak =  Virama_Final:];
+VI = [:LineBreak =  Virama:];
 WJ = [:LineBreak =  Word_Joiner:];
 XX = [:LineBreak =  Unknown:];
 ZW = [:LineBreak =  ZWSpace:];
@@ -79,6 +84,9 @@ ZWJ = [:LineBreak =  ZWJ:];
 OP30 = [OP - [\p{ea=F}\p{ea=W}\p{ea=H}]];
 CP30 = [CP - [\p{ea=F}\p{ea=W}\p{ea=H}]];
 
+PiQU = [\p{Pi}&QU];
+PfQU = [\p{Pf}&QU];
+
 # The redundant-looking inner brackets are required for the current parser in the test code.
 ExtPictUnassigned = [[\p{Extended_Pictographic}]&[\p{Cn}]];
 
@@ -110,19 +118,27 @@ LB8:        ZW SP* ÷ [^ZW SP BK CR LF NL];
 LB25:        ((PR | PO)CM*)? ((OP | HY)CM*)? (IS CM*)? NU (CM*(NU | SY | IS))* (CM*(CL | CP))? (CM*(PR | PO))?;
 
 # Rules LB14 - LB17.
+
+# Moved before LB14, because it matches a supersequence.
+LB15a.1:       ( OP CM* SP* | QU CM* | GL CM* ) (PiQU CM* SP*)+ .;
+
 # Moved up, before LB7, because they can match a longer sequence that would also match LB7.
 # For example, the sequence "OP CM SP AL" matches LB14
 # while the prefix of it, "OP CM SP" matches LB7.1
 LB14:        OP CM* SP* .;
 
-# LB 14a Break before an IS that begins a number and follows a space.
-LB14a:       SP ÷ IS CM* NU;
+LB15a.2:       ^ (PiQU CM* SP*)+ .;
+# LB15b/LB15a chaining.
+LB15b.1:       ([^SP] CM* | SP) PfQU CM* (PiQU CM* SP*)+ .;
+LB15b.2:       ([^SP] CM* | SP) PfQU CM* ( SP | GL | WJ | CL | QU | CP | EX | IS | SY | BK | CR | LF | NL | ZW | $ );
 
-# LB14b       × IS
-LB14b.1:     [^SP] CM* IS;
-LB14b.2:     SP IS;
+# LB 15c Break before an IS that begins a number and follows a space.
+LB15c:       SP ÷ IS CM* NU;
+
+# LB15d       × IS
+LB15d.1:     [^SP] CM* IS;
+LB15d.2:     SP IS;
 
-LB15:        QU CM* SP* OP;
 
 # Do not break between closing punctuation and $NS, even with intervening spaces
 # But DO allow a break between closing punctuation and $NSX, don't include it here
@@ -211,6 +227,8 @@ LB27.2:      PR CM* (JL | JV | JT | H2 | H3);
 #      Unattached (leading) CM treated as AL.
 LB28:        (AL | HL | CM)CM* (AL | HL);
 
+LB28: (AP CM*)? (AS | AK | [◌] ) (CM* VI CM* (AK | [◌] ))* (CM* VI | ((CM* (AS | AK | [◌] ) )? CM* VF))?;
+
 LB29:        IS CM* (AL | HL);
 
 # LB30  is adjusted for unattached leading CM being treated as AL.
diff --git a/icu4j/main/tests/core/src/com/ibm/icu/dev/test/rbbi/rbbitst.txt b/icu4j/main/tests/core/src/com/ibm/icu/dev/test/rbbi/rbbitst.txt
index c0b6d1a55e3c..772acf24363c 100644
--- a/icu4j/main/tests/core/src/com/ibm/icu/dev/test/rbbi/rbbitst.txt
+++ b/icu4j/main/tests/core/src/com/ibm/icu/dev/test/rbbi/rbbitst.txt
@@ -2195,3 +2195,24 @@ Bangkok)•</data>
 [y] [a] [b] [c] [d] {600};
 </rules>
 <data>•ab<100>c•d•ab<200>e•f•ab<300>e•g•abch<400>xab<500>c•d•yabcd<600></data>
+
+#
+# Examples for line breaking at orthographic syllable boundaries
+# From Unicode document L2/22-080R
+#
+
+<locale en>
+<line>
+<data>•\U00011F26•\U00011F02\U00011F2D•\U00011F26\U00011F42\U00011F26•\U00011F31\U00011F41•</data>
+<data>•\u1BD7\u1BEC•\u1BD2\u1BEA\u1BC9\u1BF3•\u1BC2\u1BE7\u1BC9\u1BF3•</data>
+<data>•\u1B18•\u1B27\u1B44\u200C\u1B2B\u1B38•\u1B31\u1B44\u1B1D\u1B36•</data>
+
+# Line breaking around quotation marks (LB 15a and LB 15b).
+<locale en>
+<line>
+<data>•Some •« basic » •quoting•</data>
+<data>•Some •»German« •quoting•</data>
+<data>•( « bracketed » ) •quoting•</data>
+<data>•« « Nesting » »•</data>
+<data>•« Complex »« chaining » •</data>
+<data>•« .618 »•</data>  # Interaction with the ICU tailoring to break before such numbers.
\ No newline at end of file
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