(I hope all this background information I’m about to give is relevant.) I’m a teenager from the north side of Chicago with a mostly unplaceable General American accent. I have some general tendencies characteristic of the Inland North (no cot-caught merger, yes Canadian Raising in the PRICE set) but not others (my TRAP vowel is far closer to [æ] than the broader [eə̯] or [eæ̯], except when it precedes nasals). My father grew up in Evanston, a suburb just north of Chicago. Both of his parents are from Iowa.
I think my dad’s accent is extremely similar to mine, but I have noticed an unusual feature his speech. Since my sister and I were younger, we always joked that our dad said “pillow” like “pellow.” In more precise terms, he had been realizing the phonemic sequence usually analyzed as /ɪl/ much closer to [ɛɫ] - though there’s a chance it doesn’t quite reach as low as a true cardinal 3. I believe this realization also applies to the name of our home state, “Ellinois,” and the most popular ice cream flavor, “vanElla.” The vowel might be lowered in some words a bit more than others.
Currently, I’m doubtful whether this constitutes an /ɪl ~ ɛl/ merger in my dad’s speech. He told me he would still pronounce the words “ilk” and “elk” differently, so if there is a merger at play, it definitely doesn’t occur in all /ɛl/ words. It seems plausible that the feature could be restricted to lexical items where the sequence is followed by another vowel. However, I think his vowel in “milk” is low as well, though it’s not quite as noticeable as in the aforementioned “pillow.” Later, I will ask him about the “billow-bellow” minimal pair - I predict that he won’t pronounce them the same, but it will definitely be more interesting if he does.
I don’t specifically remember hearing the lowered pillow vowel in anyone else’s speech before, but that certainly doesn’t mean I haven’t. My dad isn’t sure if his friends from Evanston pronounce these words like he does, and he found my suggestion that the feature could be a unique Evanston characteristic rather comical. It seems even less likely that he picked up the feature from his Iowan parents alone.
I’ve never seen this phonetic feature described before, and I have no idea where it comes from. Where does this exist, and with what type of speakers? Is it a common feature around the Great Lakes that I simply haven’t noticed because neither of us have very broad accents? How should it be analyzed?