...unless the language menu is itself localized. This happens so often its not funny. Even finding the language menu is hard, since its title often localized also.
This bugs the hell out of me, what is wrong with little flag + two letter code to indicate the current language, and maybe a little arrow to indicate that it is a menu you can select from.
But it's not as easy as a bunch of flags and ISO 3166 codes.
What happens for countries where there is no official language and two languages commonly spoken? (US: English and Spanish; Spain: Spanish and Catalon etc etc.)