There's probably a word I've been pronouncing wrong my whole life that I don't know about
Just based on how often I notice someone mispronounce a word without realizing it (or have done so myself and realized it later). Statistically I'm probably still doing it with some word.
He claimed it wasn't an accent. It was a database class. I think he was correct though as that type of thing transcends accents
He was weird. He spent an entire class talking about his divorce and once came in dressed as a cowboy. Oh, and he also taught us for mathematics, and ended up failing the entire class on coursework.
You just reminded me of my highschool AP bio teacher who was a new Englander, but lived and worked in the UK for a few years. He pronounced half like "hawf" and it was always jarring because otherwise his accent was mostly normal.