I want to know, because I cannot understand some people when they speak and I think this is because the dialect.
Regional word choice (even the difference between sneakers and trainers can be confusing to a learner), verb conjugations ("You were going" vs. "You was going," for example), idioms, slang, and accents are probably your biggest obstacles. Nothing is so drastically different that it's a total leap, but it does take some time to get used to the varieties.
Hay tres tipos principales de acentos estadounidenses. Existe el acento americano hablado en el noreste de los Estados Unidos y existen otros acentos hablados en otras partes de los Estados Unidos. Matt Damon es uno de mis actores favoritos. Él habla con el dialecto del noroeste de los Estados Unidos. Cuando a una vocal le sigue la letra R, luego esa letra "R" no se pronuncia. Me gustaría hablar este dialecto, porque se habla rápidamente, pero la letra "R" en el dialecto de la zona central de los Estados Unidos se pronuncia siempre. También está el acento sureño de los Estados Unidos, que prolonga las vocales. Por consiguiente, más tiempo se necesita para hablar de esta manera este me disgusta más que cualquier otro acento.
Since you are from Santa Domingo, Jamaica is relatively close to you. Although I would not swim it. But, have you ever heard the Jamaican dialect? You can hardly call it English. If those people were from Jamaica, well, nobody outside understands them.
Even native english speakers can have trouble with some accents. I find that people from some parts of Scotland are the hardest to understand. Especially on the phone where sound quality isn't great.
Even in Britain we have dozens of accents.
This is mine, see if you can understand it!