You’re right that if students were explicitly taught about auxillary verbs they might not write “could of”. But it seemed to me that you were confusing this sensible advice with the mistaken belief that native speakers are not pronouncing “have” correctly.

My point isn’t that people are using “have” where they should use “of,” but that they are writing “could of” rather than “could have.” If they truly understood the difference, they wouldn’t be doing it. I’m sure if you search for “could of” in quotes in Google or another search engine you’ll see many pages explaining that it is incorrect to write, but also many people actually writing it that way.

You say that it “makes sense” and that they mean “have” but write “of.” That’s partly hitting on the point. People think they hear “of” when they are hearing a less articulated version of “have.” Writing “of” means they don’t understand that it is incorrect. It’s similar to people writing “half to” as in “I have to do X.” Fortunately, that’s a much less common mistake and, I think, illustrates that in the “have to” case, people realize the function “have” is playing in the sentence. If people fully understood that it is an auxiliary verb, these two mistakes would be closer to equally frequent.

On the other hand, everyone pronounces “could have” as [kÊŠdv] or [kÊŠdÉ™] in normal speech. This is what people expect to hear, and it is what people say. It conforms to the norms of usage, and there is no breakdown in communication.

You seem to be saying that when people write “could of” or say [kÊŠdv], they don’t actually mean “could have,” they mean “could of.” This is a strange thing to say. I don’t think anyone is confused about the usage of the preposition “of” and the auxillary verb “have”. Everyone knows how they are used. If they didn’t, they might say or write things like “the meaning have life” or “the end have the day”, when they mean “of”, and I don’t think anyone does that.

What’s happening is that they’re writing “of” instead of “have” in this specific environment, and this makes sense, since “have” in this environment is pronounced almost exactly like “of”. I’m not saying that makes it right, I’m just saying that it’s a trivial respelling based on pronunciation, and not the result of confusion over verbs and prepositions.

The other point is that if people are writing it as “could of” that means when they are pronouncing it, they don’t mean “could have” they mean “could of.”

In any case, my point is: You’re right that “could of” is a mistake, but it’s a mistake to say that the spelling is wrong because the pronunciation is wrong - there’s nothing wrong with the pronunciation.

You’re right that “could of” is a mistake, but it’s a mistake to say that the spelling is wrong because the pronunciation is wrong - there’s nothing wrong with the pronunciation.

You still haven’t provided any evidence as to why [kÊŠdv] or [kÊŠdÉ™] are anything other than completely normal.

We shouldn’t rely on spelling as a guide to pronunciation. “have” is sometimes [hæv] but it’s very often [É™] or [v], even in careful pronunciation - in my experience.

eg the conjuction “that” is almost always pronounced [ðət], very seldom [ðæt]. [ðæt] is the demonstrative, as in “that book is mine.”

It’s one thing to talk about spelling errors - of course you should probably write “could have” instead of “could of”. But it’s quite another thing to say that our normal way of talking is improper.