Jessi spent days up in this little office in our linguistics hallway (this was back before I retired from Southern Illinois University) listening to people make the sound -l. L as in little. Now little has two l's, the first one being what you'd call light, and the last one being what you'd call dark. My present linguistics book, by the way, ignores this distinction. Maybe it's because it doesn't matter any more, I'm not sure. What Jessi found was that people make all kinds. Some make all light, some make all dark, some have their own kind. I find this interesting and I look forward to hearing more about it (she will send me her paper, she's promised).
She found out a lot of things. It's kind of like court reporting. Once you train your ear, and by discipline or whatever, try to become very objective, you'll notice that you become better at just recording what exactly you heard, as opposed to what you expected, or what somebody said you'd hear, or whatever. And there really is an incredible variety out there in what people say and do.
I've been pressing Jessi on a single question that is on my mind, and it's possible she won't be able to answer it based on the work she's done, which really focused on -l, and not the vowels. The question is this: there is no doubt that there is a vowel shift happening in the northern cities (called the Northern Cities Vowel Shift), and that young people, women first, are changing and moving a whole set of vowels around in their mouths. My primary example is thank you which is coming out more and more sounding like think you or at least thenk you. In other words, it's moving way up. Now Wikipedia does not consider this a dialect, although it is a whole system of shifts that are happening and have been happening since the 60's. They maintain that Canadians are not taking it up, and that though it has moved down to St. Louis, it hasn't gone much further west than say Cedar Rapids or central Minnesota. So what's up? Is it a dialect? Is it a great change that's happening in our midst like the great vowel shift of the 1600's?
Some research has been done about the reasons for the Great Vowel Shift in the 1600's. Actually it happened any time between 1300 and maybe 1650, who knows? And all kinds of things were happening then: plague was wiping out all classes; people were moving around; the aristocracy was returning to English after speaking French for a while; people were practicing social mobility for the first time ever. Also, they were beginning to solidify and standardize the writing system, which meant that words that didn't make the shift got left behind in a very visible way; their spelling became irregular.
Now my questions may be obvious. Are all sound changes dictated by social movement? (If so what is up with those northern girls?....) Is it possible that whole populations change their vowels without being aware of it? What role does hypercorrection play in this picture?
All good questions, which I will return to later, I'm sure.