could have
coulda
/ˈkʊdə/Reduction
In real speech
What happens to the sounds
have weakens to /ə/: could have → “COULD-a”.
When to use it
It coulda been worse. The phrase “woulda, coulda, shoulda” is about pointless regrets.
Casual → formal
Slang
coulda
Neutral
could've
Formal
could have
Sound notes
Reduction: unstressed words get squeezed, and their vowels turn into the neutral sound /ə/.