I've read multiple articles that state the American english accent is actually what proper English sounded like, pre the America's. Apparently it's the British accent that has changed. How true is this?

by anuncommontruth

I couldnt find this question anywhere. My girlfriend pointed this out to me trending on twitter, amd mentlefloss had an article about it as well as a few dozen others.

So is there any historical and factual basis to back up this claim?

kitchensink108

Here are a couple previous threads on the subject:

Is the American and Canadian accent the original British accent? has a pretty direct answer to your question (answer by /u/LeFourthAccount).

How and when did the "American" accent come to be? answers a different question, but still gives a lot of background info on the "American" accent and its development (answer by /u/lord_mayor_of_reddit).

cardboard-cutout

Follow up question, was the shift intentional, as a way to differentiate the proper British from the people in the sticks?