I wouldn’t imagine that such a limit would be a problem for the odd post in a mixed-language thread, but I was trying to read a thread that was all in dutch (which I can’t read) and so had to click to translate each little 3-sentence post in the thread.
If there was a way to translate all posts in a thread that would cut down on the number of clicks, but maybe that would have other issues in terms of translating from many source languages to one destination in a single larger request.