User Guide here
AutismChat is a Free/Libre Open Source Bukkit/Spigot 1.12 plugin designed by fallerOfFalls to give those on the autistic spectrum (and anyone else) more control over the chat-related stimulous they receive, regardless of the number of players online. Players can also change the colour of their usernames to indicate different communication preferences, which are enforced by AutismChat. All messages in the plugin can be modified in the messages config.
AutismChat4 further increases emphasis on party chat, making it easier to join a party, just by being green.
This plugin is still under development. Expect it to be quite broken.