Bad grammar that bugs me because it has become too common.
"Did you see the crash?"
"I seen it!"
"Have you seen the crash video?"
"I seen it!"
The responder sounds like an uneducated hick. Rarely do people want to sound like that. I hope.
The responses should have been:
"I saw it!"
In the second case, they could have said:
"I have seen it."
Maybe these hicks think they are doing better by using "seen" instead of "seed", as in "I seed it!"
I don't have to remember from English class the designations for the words, but I know what sounds wrong. Why is it so hard for some people?