How to use translations coming from files

[StefanoTesla]

I'm having some problem using translations coming fron file.

|project folder
|locales
|-it.json
|-en.json
..
|pages
|-indev.vue
..
|nuxt.config.ts

it.json file:

{
    "prova" : "prova"
}

en.json file:

{
    "prova" : "test"
}

nuxt.config.ts file:

        i18n: {
            strategy: 'prefix_except_default',
            defaultLocale: 'it',
            locales: [
              {
                code: 'en',
                name: 'EN',
                file: 'en.json'
              },
              {
                code: 'it',
                name: 'IT',
                file: 'it.json'
              },
            ],
           ...custom routes
            lazy: true,
            langDir: 'locales',
        },

index.vue

<script setup>
const route = useRoute()
const { locale, locales, t } = useI18n()
</script>

<template>
<div>
<b>{{ t(prova) }}</b>
</div>
</template>

Loking from dev bar translation are loaded, but I get 500 error invalid argument

Form log console I have:

[Vue warn]: Property "prova" was accessed during render but is not defined on instance.                                                                                             12:16:32
[nuxt] [request error] [unhandled] [500] Invalid arguments  

[StefanoTesla]

{{ t(prova) }} -> {{ t('prova') }}