English mother tongue

So, I'm curious and want to ask specifically those whose native language is english. I see this quite a lot: "...should of been..." (and similar phrases). Where does this come from? I learned at school "...should have been..." Is it incorrect nowadays? Or is it two different things?

I guess they are still learning english, there is alot of people here that their native language is not english, but some is better than others.

Comes from the contraction "should’ve"

Thank you very much.

newt

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It makes sense that it is imitative. Learned and stored (and won't use it)