Ask a native English speaker to say I would have gone, and they almost certainly produce I woulduhv gone. In spoken English, have after a modal verb is reduced so strongly that its vowel becomes a schwa and its /h/ disappears entirely. That's why native writers sometimes mis-spell it as would of — the two sound identical.
The Rule
When have is an unstressed auxiliary after a modal (would, could, should, must, might, may), the full /hæv/ reduces to just /əv/. In faster speech it reduces even further to /ə/. In writing this is spelled with the contraction 've.
- would have → would've /ˈwʊdəv/
- could have → could've /ˈkʊdəv/
- should have → should've /ˈʃʊdəv/
Practice: Reduced Modal + Have
Exceptions: When to Say Full 'Have'
Only say /hæv/ when you want to emphasize the word or when it ends a clause:
- Emphasis: I WOULD HAVE — but I didn't.
- End of clause: Yes, she could have. (here both words keep full forms)
Don't Write What You Hear
The reduced /əv/ sounds like the preposition of, so many natives mistakenly write could of, should of. That is a spelling mistake, not a real form. In writing, always use would have or would've.
Why This Matters
If you pronounce have in full every time, you will sound stiff and overly formal. Worse, you will struggle to understand native speakers because /ˈwʊdəv/ sounds nothing like the /hæv/ you learned in class.
Practice Tip
Take ten sentences with would have / could have / should have and read them aloud, pronouncing have as just /əv/. Then watch a scene from any American film and count how many times you hear /ˈwʊdəv/ or /ˈkʊdəv/ — you'll start catching it everywhere.