Once you get into it, Spanish is actually a straightforward language – and in Mexico people are desperately eager to understand and to help the most faltering attempt. English is widely spoken, especially in the tourist areas, but you'll get a far better reception if you at least try to communicate with people in their own tongue. You'll be further helped by the fact that Mexicans speak relatively slowly (at least compared with Spaniards) and that there's none of the awkward lisping pronunciation.