[addon found]
 

TESO do not support cyrillic, chinese, arabic and many other languages in chat. I'd like to have addon which will replace default chat font with font.ttf in addon folder so players who want to use their native language to communicate with friends or local guild will be able to replace this font.ttf file with any font that support their language.

Check this out: http://www.esoui.com/downloads/info55-Pawksickles.html

I've seen it but this addon is overkill. It includes massive libraries that may cause compatibility issues and change all fonts in game instead of just chat.