If people mispronounce certain words & have heard hundreds of others pronnouce them the right way, why won't they change the way they pronounce them?

I'm listening to a video where the first guy speaking pronounced "deal" and "scale" as "dill" and "skell". I'm SURE he's heard them spoken the correct way hundreds of times before in his 40 to 60 years of life but, he still refuses to say them correctly.
I'm sure there were words I said the wrong way when I was little, as we all have, but eventually learned the correct way to say them. My cousin's son used to say, "hangaburger" but now says, "Hamburger", another cousin's son from Lubbock, Texas used to say he's from "Yubbock". Now, he says, "Lubbock'.

If people mispronounce certain words & have heard hundreds of others pronnouce them the right way, why won't they change the way they pronounce them?
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