Following a reference in Language Hat to the Northern Cities vowel shift, which is described in some detail at a PBS site on American English, I’ve just spent a pleasant hour reading about vowel shifts, the quotative ‘ like’ (as in “I’m like ‘What’re you doing?’”, the rising intonation (“Hi, I’m Heather? I’m in your class? I have a question?”: see Carmen Fought on dialects at the PBS site), and other idiosyncrasies of American speech. The Atlas of North American English, under the direction of William Labov, distinguishes half a dozen major regional dialects, and another half dozen smaller or more restricted dialects (not counting creoles or hybrids like Chicano English or Louisana Creole).
My own speech patterns no doubt reflect my upbringing in Cincinnati (Midland, on the border with Southern). Saint Louis is, rather strikingly, part of what Labov calls the Northern dialect, whose heartland is the big cities around the Great Lakes; a finger extends southward from Chicago through Springfield to include Saint Louis (but nothing else in Missouri: see p66 from Chapter 11 in the pdf version).