After some bad calls using search/replace, I'm curious how many legitimate forms of "could/would/should of" there are. I'm interested in uses that do not derive from, and cannot be replaced by "could have," "would have," "should have," or their contractions.

One could of course add a few commas to this paragraph to make it easier to read, but I'm not sure that would of necessity be the only correct way to punctuate it. I frequently see constructs like "of itself," "of course," "of her own volition," and so forth in print without being couched in commas.

Still, I wouldn't make as big a deal of that example as I would of this one.

What other legitimate patterns for their use might there be, and are there any foolproof rules for helping identify them? (e.g. Is it safe to say that "would of [verb]" is always wrong?)

Contrary to folk wisdom saying "should of" is always wrong, it's not always wrong. Some well-formed sentences contain "should of" without meaning "should've". I want to feed someone some exceptions to the "it's always wrong" rule, and if the exceptions are rare enough (unlikely, I suppose), a list of all the cases where it's proper to use "should of."

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    I'm not sure if this question is based on a misunderstanding - the usual "shoulda, coulda, woulda" is shorthand for "should have, could have, would have", not "should of, could of, would of". "Should of" is not a set phrase, and will only be encountered spanning phrases in a sentence. You won't find any comprehensive, concise rule set about what phrases can and can't go next to each other. Commented Apr 11, 2017 at 13:19
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    I'm fully aware of that common misunderstanding. What's bothering me is the consensus that "could of" is always wrong, as evidenced here, which at least one of the examples above proves grossly over-simplistic. I was just hoping there would be a manageable number of exceptions to that rule when coaching other writers, but it sounds like you're implying there aren't.
    – Steven K
    Commented Apr 11, 2017 at 13:36
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    Here are some more examples from Google Books: google.com/…
    – herisson
    Commented Apr 11, 2017 at 17:50
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    In the combined setting, some behaviors that were once kept in the “backstage” of each performance would, of necessity, emerge into the enlarged “onstage” area. and They were subsurvient to their priest, so much so, that they would no more have thought of criticising his acts, than they would of God Himself.
    – Mari-Lou A
    Commented Apr 11, 2017 at 17:53
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    Re whether "would of [verb]" is always wrong there are many verbs which function as adjectives e.g. His wife would be more suspicious of single women than she would of married ones. ..
    – davidlol
    Commented Apr 11, 2017 at 18:48

2 Answers 2


Essentially, words are really made of sounds and not letters. The weak forms of have and of are homophones and can both be pronounced as /əv/—or in rapid speech as just /ə/ or /v/:

  • /'ʃəd əv 'left/ "should uv left"
  • /'ʃədv 'left/ "should v left"
  • /'ʃəd ə 'left/ "shoulda left
  • /'bɒtl əv 'wɔ:tə/ "bottle uv water"
  • /'bɒtlv 'wɔ:tə/"bottle v water"
  • /'botl ə 'wɔ:tə/ "bottla water"

In the position after the modal verb (would, should, could etc), the following word, /əv/, is very unlikely to be stressed in normal speech. Because the orthography of the word is just a convention, if this was always the way this word sounded, then it would be much of a muchness whether you spelled it have or of.

However, notice that I said that this word is unlikely to be stressed in normal speech. When this word is stranded, appearing with no following verb phrase, it may sometimes be given its strong form by some speakers. So here, the strong form of the word will disambiguate between have and of.

Not so fast, Ethel. The fact of the matter is that while many speakers will use the strong form /hæv/—"hav"—here, a significant number of English speakers, at least in the UK, will use /ɒv/—"ov". So for the string "I should have/of", you might hear either of the following:

  • /aɪ 'ʃʊd hæv/ "I should hav"
  • /aɪ 'ʃʊd ɒv/ "I should ov"

Now, English is always changing and evolving, and over time items are reanalysed grammatically and so forth. For speakers who use the second form there, the word arguably is the word of for them. The fact that a large number of speakers use have in their grammar does not mean that these other speakers are mispronouncing the word have. It just means that there is a dialectical difference where their grammar stipulates an ov not a hav in this position. If we see this spreading into writing, it is hardly surprising.

The Original Poster's question

So, in answer to the Original Poster's question, for some people should of might always be considered legitimate. However, for the majority of standard English speakers modal verbs like could and so forth always take a complement headed by a plain form of a verb. And these particular speakers don't happen to have a verb of in their vocabulary.

However, if the question is merely one of whether it's possible—for speakers whose dialects use have after the modal—to have a sequence of a modal verb, the preposition of, and then a past participle form of the verb the answer is not usually. The reason for 'not usually' is that the preposition of must take a complement. It never takes past participle clauses as a complement. It will only accept noun phrases, preposition phrases, and gerund participle clauses (-ing forms of a verb) as a complement. [However, it may be possible for a noun phrase following the preposition of to have a past participle form of the verb as a modifier. I can't think of an example right now, though.]

As to the question of how many ways one might have a string consisting of a modal verb followed by of, the answer is that there is no limit. If part of the verb phrase after the modal is deleted or omitted for some reason (and there are many reasons why it might be) then any adjunct or complement of a noun or adjective beginning with the word of might occur afterwards. And there is no limit to the number of adjuncts or complements beginning with the word of:

  • I couldn't find the same number of spiders as I could of beetles.
  • You shouldn't be as scared of rats as you should of mosquitoes.
  • I would take pictures of my girlfriend. I wouldn't of you.

However, having said all of that, what people like to be righteous about is not the occurrence of the word of after a modal verb. They decry the use of an of-phrase being used as the grammatical complement of a modal.

I suppose I could of told you that at the beginning. Maybe I should of ...

Here are some Language Log posts about could of et cetera:

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    @sumelic Yes, this is an enlightening, well-written and researched reply that entirely missed the point of the question.
    – Steven K
    Commented Apr 11, 2017 at 16:44
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    @StevenKath whose fault is that? Another user also interpreted your question as asking for the ungrammatical usage of should of etc. Perhaps you had better clarify that you are aware of how to use modals with the present perfect. And maybe Araucaria should have read the comments. :)
    – Mari-Lou A
    Commented Apr 11, 2017 at 17:10
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    @sumelic I did understand that. The answer to that question is given in the last paragraph (I hope), where I say "* However, for the majority of standard English speakers modal verbs like could and so forth always take a complement headed by a plain form of the verb. And these particular speakers don't happen to have a verb of in their vocabulary.*" Commented Apr 11, 2017 at 17:25
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    @Mari-LouA I thought *legitimate uses* of "should of" right there in the question would clearly rule out answers about illegitimate uses where the writer should've written "should've". Anyway, I added to the body of the question hoping it will help clear up that confusion.
    – Steven K
    Commented Apr 11, 2017 at 17:49
  • @Mari-LouA whose fault is that? But seriously, I see your point, clarity in English is a challenge better fought by the writer than the reader. I added to the question to clarify what I'm asking for.
    – Steven K
    Commented Apr 11, 2017 at 18:00

I could not find any proper uses of could of; but I could of could have.

Oh, wait...

  • You could have found enough examples from Araucaria's answer ;)
    – NVZ
    Commented Apr 16, 2017 at 9:28
  • @TimLymignton He he ;) Commented Apr 16, 2017 at 9:32

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