As far as dialects are concerned, in English like in Spanish there are many variants. Among others, we can either talk of British or American English as the most commonly used. However, both variants include different dialects with particular accents and pronunciation; as well as special words in each one.
Here is an interesting link (aschman.net "Full-Scale Dialect Map—American English Dialect"; also shared with Interlingua Events), which explains all American Accents. It's worth reading to improve our understanding of American English through learning the dialects that are spoken in each area:
Ana Isabel Ferreirós Rey.