From this thread:

Quote Originally Posted by MDKII View Post
The forums are currently English-only, but we'll open it up for other languages after a while. The languages that will be available are all the ones our Customer Care team supports.
So, to answer your question: yes, we'll support Serbian as well as all languages our Customer Care team supports (so a total of 10 more languages). I can't give you and solid time-frame right now, but it's in the works.