I don't think we have a Spanish speaker so we will have to stick to bigger airfields.
OR - you could always pickup a Spanish speaking friend along the way? Alternatively, just write down the calls, and practice a few times. It'd be a shame to lose out on so many possibilities! :-) Also - when I was there (almost a year ago today), some spoke Spanish on frequency, so it might not be so different anyway!
I would strongly recommend at least learning a few position calls / few common radio calls, as well as a few Spanish words, even at bigger GA airfields. I found that there were few that spoke English. Being able to have even a few words really helped me - especially for PPR where it seemed they only spoke Spanish and didn't have anyone who spoke English.
Don't let it deter you though! I hear google translate does wonders nowadays!!