I know this is obscure, but it has baffled me since my son was at USC and after a year or so in LA started saying “on accident” instead of “by accident”. This is really the first time I have seen this grammatical error in print, although I ran into another person from LA who says it all the time. My son quit saying it after he was back on the east coast for awhile. Can anyone tell me the origin of this strange change of a prepositional phrase? Don’t be too unkind; I really want to know.
I think it comes from the phrase “on purpose”, as in “I hit her on purpose.” You wouldn’t say, “I hit her by purpose.”
I do agree with you. It’s wrong. “By accident”, then “on purpose.” Not “by purpose” or “on accident.”
The last part of speech that one masters is the preposition.
I have always said, “by accident.” My four children, all homeschooled since my oldest was in third grade, always said, “on accident,” despite my correcting them repeatedly. I just assumed it was something everyone said in FL, because I had never heard it before until they started saying it. Now they are all grown, but I really haven’t noticed if they still say it that way.