I had a boss who mispronounced height, he'd say heith,
We were testing tube height behaviour in a automated blood testing system so it came up a lot, I posted the Wikipedia page on my office door and laughed at him every time he said, but it eventually got old for him. But for me it never lost its slithery edge ICK!!!!!
My surveying teacher at college pronounces lonJitude instead of longitude. I've checked all dictionaries, the J sound is correct even in Britain, however it seems certain parts of Australia tend to mispronounce it too, but since they don't have their own dictionary I'm declaring it JUST PLAIN WRONG!
Tho (on purpose, I like it that way) my first language is English, my education language is French, and my culture is mostly French, so English is not my better language, and I try not to have too many pet peeves in this area :)
I hate it when food producers cheat on food terminology and ingredients:
Whipping cream with 10 ingredients but no cream
Buttermilk that ain't
Sour cream with 10 ingredients
Dehydrated bananas with lactoserum
Shredded cheese made of starch
Spaghetti sauce made with starch
ALL foods made with cornstarch
This may be our biggest epidemic!