Re: 7X11 The Crimson Horror(Grading/Discussion)(SPOILERS
Academic studies... basically, the early American accent was derived from the standard accent of 17th century England, and then we both diverged, but the philological studies of spelling and so on suggest that some American accents are probably closer to 17th century English than anything currently in use in England.
There can't be any certainty about it in the absence of recordings, but the linguistic analysis heads that way.
"Some days are better than others. They say that where I come from."
"Loudly, I imagine, on the day you left."
(Blake's 7 - Rumours of Death)