My favorite experience doing exactly what you mentioned was staying in a town called La Paz, a seaside place on the Baja and going to school called Se Habla La Paz….google their website. This was such a great experience. They also arrange for you to live with a mexican family, so you are totally immersed. I have met so many wonderful people and have had so many great experiences, I highly recommend this. They also have a sister school in Guadalajara, because I wouldn’t want to be in one place for too long. I would recommend moving around and enjoying the different towns and cultures.

Remember you cannot stay in Mexico for more than 180 days at a time on a tourist visa.

good luck!

I was going to recommend La Manzanilla between Manzanillo and Vallarta with a good school
http://www.lacatalinaschool.com/

Actually there are many small towns between Tepic and Manzanillo I would consider safe but not many with schools.
I live in Melaque and hour north of Manzanillo, very safe but hot and humid in the summer like most/all of the coast.

I personally don’t like Acapulco that much, the tide is too strong to swim in the ocean and there’s a lot of garbage on the beach, not much to do (unless the city has become interesting all of a sudden in the past 5 years I’ve last been there) and my sister has told me the villages surrounding Acapulco are very rude to tourists (kinda ironic soncidering these people live off of tourism heh).

There probably isn’t that many small cities in the coastline with sufficient people that can speak english though. If I had my choice, I’d choose a place like Taxco instead. You may not have the ocean nearby (though Acapulco will still be just a 2 hour drive if you drive pretty fast), but I really loved that small city with it’s peculiar architecture and the jewelry.. well it would be too tempting not to buy there! There would still be enough people that can speak english, but you would still have to speak spanish to get around. Haha. Plus the food is great. Gotta love Yoli lemon flavored soda.