When the first immigrants came to America from England, the accents were not the same accents that exist today. It's not that Americans stopped sounding like people in England, but that both accents changed since that time. It's also the case that there is not one single British English accent, nor was there ever; There are many accents that vary widely from region to region.

If you're interested, this question has been asked a number of times before, and there is some additional information in answers to those posts.

• Would Americans at the time of the revolution have spoken with a distinct non-British accent?

• When did the current dialect of American English diverge from traditional British English?

• When did Americans lose their Brittish accent?

• Differences in American and British English accents

• At what point in time did Americans develop an American accent (or accents, for say the north and south)?