OFF TOPIC WARNING!
I also type sometimes in an other language then English and and when you type, let's say, Dutch, the English spell-check would be unbearable.
The easy way out though is just to install the Keyboard for that language. iOS5 give you also the option between native language keyboard or English keyboard.
Yeah I did but it's an Asian language so it uses different symbols that I can't always use, or it's easier to use the English equivalent.