My suggestion is to allow a scroll down list of languages to choose from (and allow a set language as default), so you do not see new posts from other languages in the forum.

I like to look at new 'English" posts, and I do not want to see posts from other languages just because I can not read them.

Anybody that wants to see posts from other languages can choose from the scroll down list of choices and subscribed to a thread they like, afterwards they can check their subscription for any new replies.

Another positive to this, is a cleaner organized look.

- MiNuN