I’m not sure how true it was but an anecdote my social studies teacher told us was that the dialect was closer to victorian/older (not quite Old English) English and that’s how Britain used to speak. However, in my opinion, they probably confused that with Britain specifically changing to non-rhotic English annunciation post the Revolutionary War with the, now US, to further separate culture. I don’t study linguistics so maybe she was right and I am wrong though. I’ve just never happened across anything of repute backing that up.
I’m not sure how true it was but an anecdote my social studies teacher told us was that the dialect was closer to victorian/older (not quite Old English) English and that’s how Britain used to speak. However, in my opinion, they probably confused that with Britain specifically changing to non-rhotic English annunciation post the Revolutionary War with the, now US, to further separate culture. I don’t study linguistics so maybe she was right and I am wrong though. I’ve just never happened across anything of repute backing that up.