I’d like to address something that has frequently been brought up in the comments. One of the most salient (and ‘exotic’) features of accents in the Western US is the way vowels behave before voiced velar consonants (i.e. ‘-g‘ and ‘-ng‘). This is especially noticeable in ‘-ing’ words: Arizonans, Californians and New Mexicans can pronounce ‘king’ as ‘keeng.’
But that’s not the only pre-velar curiosity. ‘-Ag’ words, such as ‘bag’ and ‘tag,’ can be pronounced with the vowel in ‘face.’ To Southwesterners, Northwesterners, Western Canadians, and just plain westerners in general, ‘bag’ can rhyme perfectly with ‘vague.’
Remarkably, people who possess this feature often seem completely oblivious of its existence. Some years back I played Jack Worthing in a production of Oscar Wilde’s The Importance of Being Earnest. The actress playing Gwendolen spoke in flawless British Received Pronunciation, with the notable exception of the line, ‘The fact is constantly mentioned in the more expensive monthly magazines, and has reached the provincial pulpits, I am told.’ ‘Magazine’ sounded curiously like ‘MAY-gazine;’ the actress grew up in the Bay Area. Even among people who are self-aware when it comes to their own accent, this feature is unremarked upon.
I can’t say for sure where these features come from. The raising of ‘a’ before ‘-g’ also occurs in Belfast, Northern Ireland, but that strikes me as unrelated. Nor are there easy answers for the tensing of ‘i’ in words like ‘king’ and ‘pink’. It’s odd that such a unique set of features is native to a region that is ostensibly a mishmash of different dialects.
At the West Coast Conference on Formal Linguistics, researchers Adam Baker, Jeff Mielke, and Diana Archangeli proposed that the raising of /a/ in words like ‘bag’ was due to a process called ‘velar pinch.’ In essence, because the tongue body is raised when making a ‘g’ sound, this impact the preceding vowel. (The same would be true of the ‘pink’ = ‘peenk’ phenomenon).
American accents exhibit other types of this ‘velar pinch.’ The raised American ‘a’ in ‘can’ and the pronunciation of ‘bang’ as ‘bayng’ are most likely other examples. But this doesn’t entirely explain why Western Americans extend this effect to ‘pink’ and ‘bag’ where Eastern Americans do not. Why has this feature managed to spread so far and wide? (I’ve heard it as far east as Ontario.)
I remain stumped!