I’ve also responded to this in the past, @AMT. We don’t let people work for free, for a variety of reasons. Some legal, some moral. As such, we can’t allow players to do language editing. We do pay community translators to translate the game into our various languages. 
Also, our code base is large and complex, so it’s best for our programmers to work in house for ease of communication. We aren’t interested in liaising with programmers overseas, or using unpaid labour.