UK? So far so good: Maybe those time parsing routines will need some brushing up for the 24 hour based clock, and day and month are swapped, but at least the decimal separator is the same. And it's almost the same language, and definitely the same alphabet.
France? Now you're adding accents to the mix, although in a pinch you can just drop them. (Not that it's a good idea, but there's no better solution.) But watch out: Different decimal separator!
Germany? Better rethink that "just drop the accents" solution; it changes the meaning of words, sometimes drastically/embarrassingly so. However, there is a canonical way of transliterating äöü!
Chinese: Obviously, abandon all hopes of using Latin-1. But at least you can use the US decimal separator again :)