So I got corrected today for saying “on accident” (one of my, I’m sure, many terms from the old school.) It appears that “on accident” is grammatically incorrect, but the best answer I’ve been able to find while searching Google is that it’s incorrect just because it’s incorrect.
So what is the difference between ‘by’ and ‘on’ that makes one right and one wrong?
As you have already discovered, it is for the same reason we say “on Monday” but “in February.” It’s a fossilized set phrase that you have to use as is.
But you’re not alone. This is a very common error among native speakers, and many people will unconsciously use the wrong form even when they know the right one.
Those of us who speak the queen’s English do not make such errors, not even by accident. 
[quote=“puiwaihin”]As you have already discovered, it is for the same reason we say “on Monday” but “in February.” It’s a fossilized set phrase that you have to use as is.
But you’re not alone. This is a very common error among native speakers, and many people will unconsciously use the wrong form even when they know the right one.[/quote]
Now now, being rather prescriptive there. To me, this is sort of like some people saying “She is smarter than me” instead the properest of proper “She is smarter than I.” I was brought up in the old school and the latter is what is burned into my brain as “correct,” but quite a lot of native speakers of all major dialects say the former. If students ask me which is “correct,” I’ll tell them that both are fine, but that “smarter than I” is more proper. In teaching, I think it’s important that students get the idea that there are grades of correctness and that correctness depends on situation and genre. I can’t stand it when I ask a Chinese teacher if it is considered “correct” to say something the way I’ve heard hundreds of native speakers say it, and the teacher denies that one could even say it that way just because the prescriptive grammar that he or she teaches says it is “incorrect.” Now Miltownkid, as for your original question about “on accident,” don’t you fucking know that that is just plain wrong? My god man, do you have any education? You should be embarrassed for even asking. 
i’ve never heard “on accident” before.
that being said, the only problem with teaching students that there are levels of correctness that depend on different things is that the majority of them don’t care - in the taiwanese EFL context, english is by and large a testable subject, not a language. it doesn’t matter what native speakers say on a daily basis - if their school teacher didn’t learn it (or read it from the grammar book) in that way, it’s a zero (or even better, -1 for “guessing” :s )
however, i do agree with you that people interested in really learning the language need to be made aware of these kinds of things. too bad the focus is on grammar-based tests, rather than language acquisition.
[quote=“puiwaihin”]…it is for the same reason we say “on Monday” but “in February.” It’s a fossilized set phrase that you have to use as is.
But you’re not alone. This is a very common error among native speakers, and many people will unconsciously use the wrong form even when they know the right one.[/quote]
Like “on purpose” but “by accident.” Sometimes it’s just a slip of the tongue. Who made up rules about which preposition to put in front of “purpose” or “accident” anyway. Klayzee.
Ok, back to my meds now. Night.
Never heard anybody say “on accident” before…
I’ve never heard of “on accident”, so it sounds totally wrong to me. I grew up with very standard American English, and my mom taught English. However, there might plausibly be regional or “non-standard” as well as foreign variants which use this.
I suspect the difference here is one of meaning and declension (dative v. ablative) that goes back to Latin roots.
in March, on Sunday? In - because it refers to a certain time period in a larger time period. On- is more specific. But perhaps it’s also structurally built-in.
At: Hour
On: Day
In: Month or Year.
Again, I suspect this may have to do with its Latin origins. Sometimes there is no why, just memorize.
There might be some logic to the “by” usage…
How did you learn?
“By” studying dumbo.
How did you find it?
Oh, “by” accident really, I was walking down…
it’s pretty common in certain contexts in new york. “did it on accident” comes to mind. maybe influenced by “on purpose”? as a counter-example no one would say “it happened on accident”.
Add my name to the list of those who have never heard “on accident”. Could it be one of those Americanisms that results from the influence of some immigrant language other than English (like “different than” - possibly influenced by the German anders als)? Not German (zufaellig or durch Zufall = “through” accident), nor Dutch (per toefal = “by” accident), nor French (par accident = “by” accident), nor Spanish (por accidente = “by” accident)…
It is because the phrase is a shortening of “By an accident” as in, it was the occurrence of an accident that made the situation :blah:
I was always told in college not to use either one. “Accidentally.”
I accidentally ate his sammich.
I ate his sammich accidentally.
I was told that a very uncommonly used phrase “it happened by accident” was the only time it was proper.
Why am I awake. I must be tired if I care 
upon accident is also correct, could be derived from that…
I agree. I’ve heard the phrase before and I believe most people use it intuitively to counter “on purpose”.
I’ve only heard “on accident” spoken by kids, usually interference from the phrase “on purpose”.
Someone called
Yinzer all wrong. That’s all I gotta say 'bout it.
Ninjas don’t have accidents, everything is a carefully planned and perfectly executed move.
I wouldn’t call it an “Americanism”, as I’ve not heard it in Illinois, Ohio, Kentucky, Texas or California. It might be a more local thing, e.g., New York. Or perhaps it runs in the vernacular of certain subcultures?