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.
Kind of a cop-out, since that's a straight-up French loanword. "Soften" would be better. Or "often," if not for the fact that it's so commonly mispronounced.
True! I just remembered that there was a way to make the whole word silent but didn't remember the T bit so I looked it up. This was the first example. Soften is much better!