All flying in Mexico is strictly on a flight plan. Most of the radio is in Spanish. Controllers and other pilots at anything other than international airports speak little or no English or a form of English known only to themselves!
You don't say what part of Mexico or whether you intend to fly from the USA.- it can be difficult to find a half reasonable aircraft to rent and fly from the US into Mexico and there are all sorts of border problems.
Things work a little differently in Mexico outside of the costa del holiday resorts!
I would suggest that you try to find somebody to rent you an aircraft first, that may be trickier than you expect!
[This message has been edited by Sensible (edited 22 February 2001).]