OKAY YOU GUYS I HAVE AN ACTUAL PHD IN DIALECTOLOGY
Here's the deal.
There's about seven different relevant word classes here. We can refer to them by keywords: TRAP, GLASS, START, FATHER, LOT, CLOTH, THOUGHT.
In any dialect, more or less all the words
within a class have the same vowel. For example,
trap,
flat,
cat, and
alas are all in the TRAP class and all share the same vowel sound. (There are some exceptions—words that are in one class in some dialects and another class in other dialects—but those are the exception rather than the rule. For instance
clerk is in the NURSE class in the US but the START class in England.) But
between dialects, the same class might be pronounced differently. So those four words in the TRAP class all have the same vowel, but in California it's a vowel that's low in the mouth while in Chicago it's a vowel that's relatively high.
However, in any given dialect, it's possible for two or more different classes to have exactly the same sound (while those classes are different in other dialects). For instance, in Canada, LOT, THOUGHT, and CLOTH are all the same; in New York CLOTH and THOUGHT are the same but LOT is different, and in London LOT and CLOTH are the same but THOUGHT is different.
What this means is that questions like "Do you say 'faunt' or 'hont'?" are generally going to be meaningless to people. If they have the same vowel in
font and
haunt, it's (probably) because their LOT and THOUGHT vowels are the same. So asking a question that amounts to "Do you have
font in THOUGHT or
haunt in LOT?" is unanswerable, because they're both true.
Overall:
TRAP is usually low and front in the mouth. In US cities along the Great Lakes, like Buffalo, Detroit, and Chicago, it's often higher.
In most dialects TRAP and GLASS are the same. They're different in traditional New York, Philadelphia, and Boston dialects, as well as in southern England and closely related dialects such as Australia. There is a lot of variation in terms of which words are in the GLASS set. In New York and Philadelphia, GLASS is raised like TRAP is in Chicago.
In traditional Boston, southern England, and Australia, GLASS, FATHER, and START are the same. This vowel is low and central-frontish in Boston and Australia, low and back in England.
In the rest of North America (except maybe New York?), FATHER is the same as LOT. This vowel is low. In the Great Lakes cities, it's central-frontish like the FATHER vowel of Boston; elsewhere it's mostly relatively back. If it's merged with THOUGHT, it might be produced with the lips rounded (or might not).
In North America, CLOTH is mostly the same as THOUGHT. Elsewhere, it's mostly the same as LOT, except for maybe some old-fashioned English accents.
LOT and THOUGHT are the same in Canada, northern and eastern New England, western Pennsylvania, the western US, and probably Scotland, as well as an ever-expanding set of other places in the US. They're different in (for example) New York and Philadelphia, more traditional accents throughout the Midwest and South, and most places outside North America (except Scotland). When they're different, in the US LOT usually has the lips unrounded and THOUGHT usually has the lips rounded. In England, they're both rounded, but THOUGHT is higher in the mouth. THOUGHT is high in New York and Philadelphia as well (the stereotypical "coffee talk" vowel).
Font is LOT.
Can't is GLASS.
- (Note that no dialects as far as I know have GLASS = LOT, so things like "for non-NA English 'can't' rhymes with 'font'" are misleading. What you're actually trying to say with this is that in e.g. southern England GLASS = FATHER, but you interpret this as meaning GLASS = LOT because for you FATHER = LOT. But this isn't true in England.)
Want is mostly LOT, but in some dialects it's STRUT.
Don is LOT.
Dawn is THOUGHT.
Cart is START.
Cot is LOT.
Caught is THOUGHT.
Haunt is THOUGHT as far as I know, but if someone wants to tell me it's CLOTH or LOT I'll believe them.
Aunt is mostly GLASS, but in some dialects it's TRAP.
Gaunt is THOUGHT.
Aren't is START.
