I was under the impression that all Americans pronounced aunt like the insect, ant (/ænt/), or relatively similar sounding variants such as the southern aint (/eɪnt/). According to both Webster and ODO, some Americans pronounce it as ah-nt (/änt/, /ɑnt/, or /ɔnt/) which is pretty close to the British ah-nt (/ɑ(:)nt/). Webster offers a similar alternative for the contraction, can't.
Who are these Americans who favour the British pronunciation?
/eɪnt/,/ænt/,/ant/,/ɒnt/, and/ɔnt/. See, those aren’t that hard, are they? And now we all know what everyone is talking about. – tchrist Jan 02 '13 at 23:14/ä/and/or/ɑ:/to be non-standard when both referenced dictionaries and Wikipedia consider otherwise. – coleopterist Jan 03 '13 at 05:14