Everyone should study Spanish. Everyone. And the place to go is Guatemala, where you can spend about $125 for room/board AND 20 hours of private instruction.
About a decade ago, I went to Quetzaltenango (Xela) and studied Spanish two weeks at Juan Sisay School. Better place for it than the more popular Antigua in my opinion — Spanish-colonial town surrounded by volcanoes, witch villages, rum-drinking saints and hot springs. A far fewer gringos to tempt you back into English. The school, like many there, organizes volunteer programs to help local Mayan kids learn English. One night we put on a play for them, with the mixed-bag of foreigners playing the animals of the jungle. I was the sloth.