I would like to change the language of the chat interface, I tried changing the language in the component configuration, and also changing the language in the joomla configuration, but it doesnt work.

Thanks in advance for your help

As per our discussion, I'll be activating auto language option, but, I think joomfish is using abbreviation of languages, not full name, i.e.:

Joomla uses english, joomfish uses en, is this true?
(BlastChat follows joomla design and we preffer to use english instead of en), otherwice there are only more and more duplicates of same lanuage.

I know there's a "$lang" variable that can be passed through the URL (GET) and it uses those language codes : en, de, etc.. But this ist configurable through the component (jommfish) configuration. I've just reconformed that joomfish changes also $mosConfig_lang, and the values that it can take are the names of the language files.. .i.e. I've just installed the language package germani (german informal) and I've included a "echo $mosConfig_lang" in the blastchat module, and it shows germani or english when I change the language with joomfish.

Lovely, in that case, after I adjust blastchat your joomfish installtion will be supported automatically.

I checked today but it is still not working, please let me know when have made those changes so I can check if the problem is somewhere else.

Changes have been made, little checkbox "Auto" next to language selection needs to be checked in server configuration. After that blastchat picks language defined by mosConfig_lang when client makes his initial cnnection to blastchat service.