American vowels in ''cot'' and ''caught'', no /O/ in ''caught''.

"/Q/ is generally not in North American English at all. Most NAE dialects merged /Q/ with /A/, the "father-bother" merger, while a few New England ones merged /Q/ with /O/. Either way, /Q/ is gone--even if it is produced by Americans somewhere it's unlikely to correspond to RP /Q/."

To be fair, I'd say a good number of UK dialects don't feature /Q/ either. In fact, I would argue that the following split is more common in British English nowadays:

"cot"=/kOt/
"caught"=/ko:t/

Also, a clarification:

There are actually many parts of the American western that merge the words as /kOt/ rather than /kAt/. Northern California, Washington State, and Utah all use this pronunciation.

Good point about UK dialects, Ben--I was just referring to RP because I had to pick one. And, yeah, that's basically what I was saying about the "cot-caught" merger...that it can be /O/ or /A/ or in between. At least in California, the California Vowel Shift has consistently been moving /A/ up closer to /O/, even in words like "father," so that obviously affects the "cot-caught" merger, as well. I wouldn't be surprised if something similar to the CVS is occurring in other Western US states, also. Besides serious research confirming this, the jocular spellings seen used in ways like "oh my Gawd, my mawm's here" are evidence of that.