Although all the dictionaries I've checked give /"r{D@`/ or /"rA:D@/ (AmE and BrE respectively), I think I've often heard ["r\VD@`], at least from NAE speakers, especially in the phrase "I'd rather". Can any native speaker confirm this?
Pronunciation of rather
I'm a native NAE speaker (from Massachusetts), and I've never heard this pronunciation, although I think I may have seen some references to it in the past. I pronounce it ["r\{D@`], as do most people I know; I've heard ["ra:D@] from people with traditional Eastern New England accents, and I've occasionally heard ["r\A:D@`] from rhotic North Americans on TV.
Sorry, ["ra:D@] should be ["r\a:D@] above. Also, I should mention that there is a colloquial term "druthers" - found in contexts like "If I had my druthers [ie, my way, my preferences],..." - which is derived from <'d rather>, seeming to indicate a dialectal pronunciation of [r\VD@`] at least in the past.
In the dialect here there formally is ["RE{:DR=:], equivalent to General American ["r\{:D@`]. However, my dialect frequently has the pronunciation ["RE{::R] in everyday speech.
I forgot to say that I am from Milwaukee, which is in southeastern Wisconsin.
I wonder if I heard that pronunciation from Canadians and I mistook their [a] for a realization of /V/. By now I've become used to the NCVS tense /{/ so other realizations really stand out.
In the US, I've heard both [rAD@'] and [r{D@']. I'm not entirely sure if it's regional or not.
I think there's a regional cluster of /"r\A:D@(`)/ among speakers in Eastern New England who have the trap-bath split, but I've also heard /"r\A:D@`/ from some North Americans who aren't from New England and don't otherwise seem to have the trap-bath split. So perhaps you could say that it's partly regional and partly cosmopolitan.
In RP ''rather'' has /A/,
in shifted Canadian and WestCoast US accents, ''rather'' has a vowel close to /a/.
This fronting is present across the WestCoast, even in those speakers who don't have the whole shift, only A is shifted, but other vowels stay where they are, so ''last:lost'' can have only a front-back contrast in California: last /last/ : lost /lAst/, in RP /lAst/ means last, /last/ is last only in some nonRP varieties of South England English :)
in a Harry Potter movie, they pronounced LAST as /lAst/ in the same way Californians would pronounce the word LOST :)
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Canadian and West Coast /AE/ sound just like an RP /AE/, its realization is closer to /a/ than it used to be...''flash, smash, (Californian) bag'' sound the same in Canada, California and RP... but, ''rather, fast, last'' do not, they have a back vowel in RP, and a front vowel in Canada/WestUS.
in shifted Canadian and WestCoast US accents, ''rather'' has a vowel close to /a/.
This fronting is present across the WestCoast, even in those speakers who don't have the whole shift, only A is shifted, but other vowels stay where they are, so ''last:lost'' can have only a front-back contrast in California: last /last/ : lost /lAst/, in RP /lAst/ means last, /last/ is last only in some nonRP varieties of South England English :)
in a Harry Potter movie, they pronounced LAST as /lAst/ in the same way Californians would pronounce the word LOST :)
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Canadian and West Coast /AE/ sound just like an RP /AE/, its realization is closer to /a/ than it used to be...''flash, smash, (Californian) bag'' sound the same in Canada, California and RP... but, ''rather, fast, last'' do not, they have a back vowel in RP, and a front vowel in Canada/WestUS.