I read somewhere (and doubted it) that the British accent of our revolutionary period was very much like today's American accent, and their current accent came later.
Of course, one encounters all sorts of accents in Britain, but I mean the more typical "TV accent". I've met a few Germans who I thought were Brits because their English was so good. My step son speaks accentless American English and French which is impressive to me, both like a native. The wife has a nice French accent. It's interesting how good her English is until something gets technical, or financial, or medical, etc. That makes sense, you wouldn't learn what "death benefit" means in French class, or Required Minimum Distribution.
I may be busy next week as the wife goes in for a "hip revision". Interesting term, I've had to translate a lot of medical jargon for her of late.