I have noticed that even native English speakers make grammatical errors when it comes to verbs. For example:
- I should not have came here.
- I haven't did this for a long time.
- We have went to the cinema.
- We were all stood on the barrier and saw it happen.
- Where would you like to see your product sat in the supermarket ?
- I am amaze !
Please explain whether these sentences are simply bad English or some dialect.