Could somebody please provide a potted history of US English pronunciation.

I'd heard that, to some extent, US pronunciation reflects the way the founding fathers spoke at the time of their arrival in New England. Once the vocabulary, pronunciation and dialect had been "exported" to the new land, the opportunity for a divergent evolution of the 2 "languages" had been cast.

How true is this?

Following this line of thought (and if the above is true), could one assume that the New England accent (being the oldest), is the most reflective of the language that was spoken in England whenever it was that the FF's arrived? (stales - an aspiring wordsmith maybe, history student - NOT!)

Similarly, does US English's shortening of "our" to "or" (eg in "honour") reflect its Old English origins, or is it a more recent development?

(Despite being born in Lowell, Mass, I've been an Aussie ("ozzie" NOT "ossie" - please!!) all my remembered life,so this question has a degree of personal interest).

Stales