I read somewhere that the modern British accent didn’t come about until the late 1600’s to 1700’s and was initially only used by the aristocracy. Also, that the first “Americans” probably sounded more like modern US Americans than modern Brits. Also, also that Shakespeare had more of a modern “American” accent than a British one. It’s always bothered me in movies like The Patriot that early American settlers don’t have British accents. But if the above is true, I’d now have to applaud them for historical accuracy.