I did not understand exactly about the "extension for multilingual "
I have three language files "com_community.ini" in the "languages" folder (German, English, Russian), but only on the home page (on the wall where you can write a new message), if you switch to Russian, then numbers instead of letters. But on the "Profile" page, on the wall - everything is fine, the letters are as they should be.
You can check yourself. The language is switched on the front page at the top.