The main language spoken here is Spanish, but there is slang specific to the Dominican Republic, which is difficult to learn and keep up with. Sometimes when I am speaking to Dominican students, they will joke around about how my Spanish is so proper. I think that it is important to learn both so hopefully I will keep up with it eventually!
Dominican pesos are used in the Dominican Republic. For every American dollar, I can get 50 Dominican pesos so my money goes a long way here. I can take public transportation around the city for 25 pesos which is 50 cents. I can take public transportation to Puerto Plata (which is where the beaches are and its 2 hours away) for 500 pesos which is $10. Besides that, the most I spend at a time is $4 for a snack or a smoothie on campus.
I have not bought a bottle of water because fresh clean water does not come easy here so I always fill up my reusable water bottle at home. I did buy a gallon of water for the beach and it was 85 pesos which is less than $2 so that gives you an idea of how much a bottle of water costs - its cheap!