TL;DR:Player-Inclusive Racial Languages and Automatically split long messages over multiple messages
The two main features of the addon currently are:
Non-Obfuscating Racial Languages
Converts any messages that you write in your racial language (i.e.; Thalassian, Troll, etc.) to your faction's common language (Orcish/Common) and prepends a language tag to it in the same style as the normal in-game languages.
The purpose of this is to allow people to seamlessly appear as though they're speaking in a racial language without excluding other RPers (of different races) in their vicinity from the RP.
Any time my characters spoke in their racial tongue but in the presence of my RP friends who played characters of a different race, I'd manually copy/paste "[Thalassian]" or "[Gutterspeak]" or whatever before my messages so that they (the player, not the character) could understand my character's speech in OOC terms even if their character could not in IC terms.
I got tired of doing that, so I wrote an addon to do it for me.
This also has the added benefit of preventing accidental racial language use in guild chat and so on, similar to Halya's LanguageCycle addon.
In addition, an optional language button can be used to quickly switch between available languages; inspired by the same functionality in LanguageCycle.
Chat messages longer than 255 characters
This module of the addon allows you to type long messages into your normal chat frame (exceeding Blizzard's normal limit of 255 characters) and then automatically splits the message up into multiple messages which are sent one-after-another to allow players to write longer messages to each other while working around Blizzard's message length limit.
In Bladesong we use our officer channel as a secondary means to RP with each other in a more narrative style than one ordinarily would in-game and this often means that people write longer messages describing the situation or their character's actions. It was frustrating having to manually split our messages (and potentially have them cut in two by someone else posting a message of their own before we finish ours), so I added this feature to the addon.
I've made an effort towards making KayrChat compatible with other chat-related addons such as LanguageCycle and Misspelled, but I can't test it against every possible addon combination so there could be conflicts.
Individual features can be fully disabled or enabled at any time, so if you only want one or the other feature you can mix & match.
The main reason it took me so long to actually get around to releasing an addon is that I decided a long time ago to try developing my own addon framework because I found that I was re-writing similar code too often across the 4-5 main addons I was working on (and I just didn't really like the way other frameworks were laid out).
That effort manifested as KLib, which helped me to quickly prototype KayrChat (and another 5 yet-unreleased addons).
KLib will get its own dedicated upload eventually; once I've done a lot of tidying-up of its code and written documentation for other addon authors to use it.