Having the keyboard language set to a non-roman alphabet-based language (at least in my experience), in my case Japanese, starts to fill in the chat bar with your inputs as you play the game. Eventually the game starts to lag horribly. 

Upon opening the chat, no characters appear, but after changing back to the roman-based language, the characters inputted appear.

Note: I havent' tested this on other systems and other languages, but I would give it a check.