Help, please. Language changes when I try to type

Since I bought myself a new laptop and started playing the game on it I sometimes screw up my chat bar. It goes from typing in english to... some other language. I don't know how I do it every time or how to get rid of it other than exiting the game and restarting it.
How do I prevent myself from accidentally activating this useless (to me anyway) feature? What's the hot key to disable this if anyone knows? Thanks!

Alt-shift back to the language you want. I'm presuming you want English, so alt-shift until the little white-and-blue character indicates an 'A'.

I'm sorry, I'm not sure how to disable it, but at least now you know how to turn it back ^^;

Alt-Shift or Alt-Ctrl depending on your settings
to disable it you must go to your Regional Setting in Control Panel, go to the Language tab on top and then Details. just delete everything else other then english there
that's how you do it on a XP machine anyways, not sure about Vista

Mine often switches to French... I just click on the start bar, and change it. Though sometimes it doesnt seem to want to do it :S

Thank you very much for the answers! Now I don't have to key mash my keyboard until it fixes itself at random.