I agree only that the translation should be applied in the chat only, mainly to facilitate communication between two people who speak different languages. And some have even difficulty with English.
As the "most important things" this post is in an area that tells suggestion, that is, is just a IDEA. And all ideas are welcome right?
I agree with you, today, even in mobile gaming is no such translation option, identifying the language, and translating for her. For some players who no longer have so easily to understand English is completely lost in the game.
It would also help if you had a kind of private window when you whisper to another player, so not there would be a mess as it currently is.