Why, in the expression 'should have', do so many people incorrectly say 'should of'?

Question

Example:
'He should have stayed at home'

It's the same with all the modal verbs where they are followed by 'have':

'He could have done that better'
'She would have come, but she's in Vienna'
'I must have left it at work'
'You needn't have bothered'

Answer 1

Not only that they even use the wrong form for the verb that follows. For example, could went instead of could have gone....

Answer 2

Contractions and expressions like these are further fascinating examples of the variations applied by many to our rich heritage of the English language!
Not to be taken too seriously. Let's face it, many of our favourite song lyrics are full of word variations, which if corrected, would sound ridiculous!

Answer 3

There is absolutely nothing wrong with people SAYING what sounds exactly like "should of". Pronouncing the "have" in full sounds extremely stilted in most contexts. It's only wrong when they spell it "of". That happens because they know it sounds like that...

Answer 4

when people say "should have" or "should've", it sounds like "should of", unless they are really strict with enunciation. Also, schools are pretty lazy with teaching students proper grammar, as they are with teaching students how to properly spell "grammar"

Answer 5

It's because people love contractions so much ("should've", "must've", "needn't've"(??)) in speaking that those contractions end up sounding like "should of", then leading people to commit the biggest mistake in English and spell like it sounds.

Answer 6

I think because when we speak, we don't always speak grammatically correct, so it sounds like "shoulda"..which some people will write as "should of".

Answer 7

Because as one poster mentioned they're saying "should've" which is short for should have.

Answer 8

It just sounds like it but it really isnt.

Answer 9

They don't. They are actually saying "should've".

Answer 10

poor grammer