Please state in which country your phrase tends to be used, what the phrase is, and what it should be.
Example:
In America, recently came across “back-petal”, instead of back-pedal. Also, still hearing “for all intensive purposes” instead of “for all intents and purposes”.
That’s a dialectal difference, not an error.
Not when written
I mean no? The have in could have is pronounced the same as of, but at least AFAIK no dialect explicitly says could of. Tell the other person to not mesh the two words together and they’ll say have. I think.
Minor nit pick from my experience. If the word is written out “could have” I enunciate the entire word. I only pronounce the contraction “could’ve” as “could of”. And vice versa when dictating.
It’s very much not recommended, and generally seen as an error. But this article puts an asterisk on it.
https://www.merriam-webster.com/grammar/whats-worse-than-coulda
I am viscerally against this concept.
It’s one thing to include the spelling as a way to capture the phonetics of an accent or a dialect, entirely another to accept its use in writing when using a neutral voice.
If anything, because it’s so often just a misspelling I would avoid trying to use it as a phonetics thing just as a matter of style. At this point everybody would think I’m making a mistake instead of trying to mimic a way of speech in a way they’d never do with “coulda”.
With you on all counts.