The phonology update to my last post sent me to the Wikipedia article "Free Vowel," where I found a name for something I've been searching for.
A side effect of working simultaneously on reading programs for our respective children: My two friends and I have discovered that we all talk funny, at least to each other. "What do you mean you pronounce dour 'dow-er?' It's 'doo-er'! Look, I have a dictionary RIGHT HERE. Oh, what do you know, we're both right." Probably this is compounded by the fact that I grew up in Ohio, Melissa grew up in Utah, and Hannah grew up in Texas (though you wouldn't know it to hear her talk. Unless you can get her to pronounce dour for you, I suppose. Maybe it's because she's spent the last ten years married to a Tennessean half-Brit.)
Melissa and I argued for a while about whether the vowel sounds in hot and in law were two different phonemes --- that is, whether to teach them as two different sounds --- or whether they were really the same phoneme, /o/. She said they were the same. I insisted that they were different and that treating them the same must be some weird regionalism unique to Utah and Minnesota: "I sleep in a cot. I caught a fish. Look, THEY ARE DIFFERENT WORDS AND THEY SOUND DIFFERENT. TOTALLY DIFFERENT." She would say patiently, "I can see that your lips are moving differently but they are the same." Finally we went to the dictionary, which proved to my astonishment that cot and caught are, in "standard" English, homonyms. Apparently I am actually a Southerner or Cockney or some such.
But look! In the Wikipedia article on free vowels, the list of free vowels includes both sounds:
/(phonological symbol)/ as in paw (doesn't occur in varieties with the low back merger).
/(different phonological symbol)/ as in bra
What's this about the low back merger? Wikipedia to the rescue again. It turns out that my observation about "cot" and "caught" has been made before (by non-rank amateurs!):
The cot-caught merger (also known as the low back merger) is a phonemic merger, a sound change, that occurs in some varieties of English. The merger occurs in some accents of Scottish English (Wells 1982, 400) and to some extent in Mid Ulster English (Wells 1982, 443), but is best known as a phenomenon of many varieties of North American English.
The sound change causes the vowel in words like cot, rock, and doll to be pronounced the same as the vowel in the words caught, talk, law, and small, so that for example cot and caught become homophones, and the two vowel classes become merged as a single phoneme. ...The presence of the merger and its absence are both found in many different regions of the continent, and in both urban and rural environments.
And there's a map! Indicating that, in fact, the cot-caught merger is rampant in a broad swath of the western U. S. that includes (aha!) Utah and parts of Minnesota. My speech happens to be untainted by this particular deviancy. (I grew up in Southwestern Ohio, an area "where speakers are transitional and inconsistent" w.r.t. the cot-caught merger.) I shall redefine the norm as MINE. It's closer to the Queen's English!
I've also been searching for evidence that wok and walk are not homophones. Melissa makes fun of me for insisting that the /l/ is pronounced, or at least that it affects the preceding vowel. The best I could find is this post at Dooce, and I'm not sure if it buttresses my phonemic theories that it involves an argument between two people raised in Utah.