First, if you hadn't done this already, turn the GPS off for a short while and then reboot. Sometimes that will clear it so the factory default (English) settings will return.
There is a built-in help file on Garmin GPS. Have you looked there?
Often times, you just click on the menu option and look in Settings and switch it to language of your choice. (Even if it's written in Spanish, you can figure out where the English choice is and set it back.)
If you don't have the hardcopy manual, here's a listing for that Garmin GPS manual:
http://www.retrevo.com/s/Garmin+200W?rt=pd