There is no "single" American pronunciation, There are many, and
they are being, or once were, studied. About 60 years ago I took a
course from a young woman who was working on a particular American
dialect. She was part of a scientific organization that did that sort
of thing. I can't recall how many dialects we had at the time or whether there have
been many new ones since then, but as part of the course we were
required to learn the code for designating the different sounds. By the
time we finished the course we could have done the grunt work for
one of these scientists recording and describing American dialects. I
can't refer to a text book for details since it has long since
disappeared. I don't even know if such a field continues to exist. But with a little time and a good dictionary I think I could still recapture the code and how to use it -- though I can't think of an reason why I would want to at this point.
I recall another class, this one in Chaucer. We were informed that Chaucer's
poetry was for a long time thought poor and irregular because his
critics had lost the sense of pronouncing fourteenth century end vowels. Even if we
pronounced his poetry properly, I thought to myself, one would still need to
learn the meaning (which has changed dramatically from his time to ours)
of his words, and so reading his poetry was a time-consuming matter which I scarcely
took beyond three or four of his far from uplifting tales -- whatever was required to pass the course.
And it isn't just the pronunciation and meaning of words historians and
literary scholars have to contend with. There are word fads and taste.
From one generation to the next what is "cool" or tastefully "in" changes. We don't in most cases talk exactly the way our parents did.
Lawrence, entertaining dark thoughts in sequestered San Jacinto