World Endeavors

I went with World Endeavors when I was in Costa Rica. It was great, but def better off if you're going to be there for a longer period of time. I was originally supposed to be working in a clinic in the country but things with that didn't work out very well because I didn't speak great Spanish, so I ended up teaching English to kids instead. The experience was great, my host family was awesome. I stayed in Atenas, about 45 minutes outside of Costa Rica. World Endeavors has other programs there as well, things with nature, teaching, many other things. If you're there for a long time, you can generally change your programs if you don't like them as well. I would learn as much Spanish as possible before you go though!

http://www.worldendeavors.com/

Good Luck!!