There are many schools in Granada that teach Spanish. In a addition to the formal schools there are many free lance teachers that work out of there homes or will teach wherever you please. There are less schools and teachers in San Juan del Sur but they are still available. I have a private tutor that I have been working with for about a month. I have gone from not understanding a word to communicating with the local people when I make excursions to Laguna de Apoyo and the Isletas. In Nicaragua the use of slang is rampant but is easily learned. Local Spanish teachers usually teach general Latin American Spanish but will teach the local slang when asked. Because real estate is becoming more and more expensive in Granada Spanish schools are moving to periphery of town.