as a foreigner, I hate T9. The first thing I do when I start using a new phone is to turn it off. It just doesn't work with short names, foreign words (or my name), or common sms slang.
Multi-language support is tough, but some implementations are better than others (there are lots of different versions of T9, you're just stuck with whatever your phone has). The latest version of T9 has support for using multiple languages at once, but most phone makers don't advertise what version of T9 they ship.
Actually, I'm a foreigner and I find typing using T9 much faster, especially because there are not as many ambiguous words (when using numeric pad) as in English.