I concur with Hillbilly and also can appreciate Matilda's humor.
What would happen if you try to learn street Spanish here is that you will be inevitably laughed at by the locals. For example, think about people you have met that spoke very poor English who tried to use all the catchy phrases with a thick accent and missing the most important words; you probably weren't impressed in the least bit and maybe even thought the person even didn't speak English - this is what the locals will think of you.
Furthermore, Dominicans don't speak a "dialect" it is Spanish with regional terms. Finally, even though Dominicans have their linguistic idiosyncrasies they are generally impressed by and show obvious respect to those who speak Spanish well - even with an accent.