Hello, my site out of the blue recognizes only the English language. How so?

Hi Domenico.

Probably your translation can be broken or not complete, I suggest to contact with team which made this translation, I'm sure they'll bee able to help you on this matter.

worked fine until this morning

Hi Domenico.

Did you maybe upgrade JomSocial or Joomla? I think it's the only thing which may cause such problem.

yes, and I solved it. Thank you

Great, then let me close this thread and mark it as solved. If you've further questions please create new thread for your problem.