User Guide here
Official homepage of AutismChat is here.
AutismChat is a Free/Libre Open Source Bukkit/Spigot 1.8 (works with 1.13) 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. Version 3 adds party chat and moves global chat (which was always problematic in AutismChat 1) to the background and makes it optional. 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.
This plugin is still under development and bugfixes are being added daily, but you can download the lastest pre-release here.