Frankfurt is more of a business city. I'd avoid it on a day trip. You have a couple options that are close, one of which is Mainz, which has an outdoor marketplace on weekends, a cathedral, and is probably a little more user friendly than Frankfurt. It has a nice shopping district if you want to pop into a couple of stores, or grab a pretzel from a street vendor. If I had just a few hours, I'd head over there instead.

http://www.mainz.de/english/entdeck/ent_st.htm

Rail schedule:
http://reiseauskunft.bahn.de/bin/det...in/query.exe/e

The trip is 16 mins from the airport and under $8 one way.

Language won't be a problem. Clerks at the rail stations speak English, as do most other places I've been to. Don't let that stop you from getting out of the airport.

[This message has been edited by tom911 (edited 02-19-2002).]