Some people say SEEN instead of SAW. It’s not correct, but it’s more or less an accepted mistake. Even some educated people, depending on where they’re from, may have SEEN as the simple past in their vernacular. Also common are COME instead of CAME and GIVE instead of GAVE. We don’t consider these people uneducated when we hear this because we realize that that’s the way these verbs developed in their part of the country. PS: I’m not just talking about the US and Canada; I’ve heard this from Brits and Aussies as well.