For example, my terminal is all in English, I have "FIle - Edit - View - Terminal - Tabs - Help" on the up bar; right-click on Terminal gives me "Open terminal - Open tab - Close windows - Change profile..."; on desktop I have "Applications - Places - System". If I log-out and select Italian I expect all is in Italian, not only something. Firefox now is in Italian, after I uninstalled previous verions and installed Firefox 2. OpenOffice needed a language change: after I did it now is in Italian. "Confogure your computer" is also all in English. I'll try to switch on more times the language with Gnome...
I hope these info could be useful to understand what's going on... :unsure: