Operating System Language Packs

Ok, Lets see here, I am wondering if for Windows XP professional there is a way to change the Language pack, so Instead of me having my english version, is there a way to change the language.

I really need to know because I am trying an experiment, well I mean since I was born around the english language, I wanted to know how I would feel like if I change my computer the thing I use most in my life into a diffrent language, to see if I get used to it, and understand it easier, Dont mind me I am pretty wierd, but it would be cool for me to learn a language on my own, instead of enrolling in a class.

Also the only reason I would think of understanding the language easier is because I know just about everything the computer says, so if its a diffrent language ill still understand what its telling me to do.