When did Americans start sounding funny to English ears? By the time the Declaration of Independence was signed in 1776, carefully composed in the richly-worded language of the day, did colonial Americans—who after all were British before they decided to switch to become American—really sound all that different from their counterparts in the mother country?
If you believe historical reenactments in film and television, no. Many people assume colonists spoke with the same accents their families immigrated with, which were largely British ones. Of course, sociolinguistic studies regularly show that speakers of American English seem to have a gentle inferiority complex about their own different accents, often rating British accents as higher in social status, for instance. So anglophone language attitudes being what they are, the accents of historical figures often end up British-inflected anyway, which, for audiences on both sides of the pond, seems to add an air of artistic verisimilitude to what might otherwise be a bald and unconvincing narrative. This might ultimately be a stretch for Romans and Nazis and evil villains. But is it really out of left field for the principal historical figures of colonial British America, on-screen or off-, to have sounded more or less British, with its tumbling mess of quirky regional dialects, a Scot here, a Cockney there, as well as the ever present Queen’s English?
Well, yes and no. The story of America’s linguistic independence is not so simple as some believe. Of course, most colonial Americans certainly did not sound like your average modern Brit does today, but nor did they sound like the Queen. By the time America was ready to consciously uncouple itself from the mother country, it had long since achieved a kind of linguistic independence. Thanks to a remarkable kind of linguistic melting pot process, early Americans spoke with a standard dialect all their own that was often met with approval by English observers, in contrast to how certain American accents are sometimes judged today.