Strange Forum keys

On my forum on haatp://www.busimatch the Keys are not _key but [L[Change Signature]]

How they works???

If you see a [L] in brackets it means the forum language has not been compiled. Go to Manage Forum as admin and click the compile link. yoursite.com/forum/?action=goto&manage_forum=1

But why it's not regular language file in /langs/ ?

It's also russian...

The forums are separate. It used to be a standalone product so the language system in the forums is separate from the rest of dolphin.

Search the forums for forum language. http://www.boonex.com/googlesearch/search?q=forum+language&gse_filter=googlesearch you will find plenty of topics on the forum languages.