The complete OS is in one language. It's located within the eproms, so you can easily change them.
If you want to have an OS in another language you can search the web as I saw one site on which they had a huge number of TOS's in different languages. Just download the one of your choice and find someone who burns the eproms for you (or do it yourself if you're capable of it).
I don't know whether there is some software that changes the language of your OS running in your auto-folder. Would be nice I think.