It would be easier just to call it American wouldn't it. I think that is the point I'm trying to make. I think, as mentioned above, Spanish has similar problems. Most speak Spanish where I live, but it isn't the same Spanish as the South Americans (large generalisation there) speak.That's what I'm trying to do, you troglodyte! In school, we wrote "English" at the top of our lesson, and on paper our language looks like English. But when watching an English movie, I need subtitles, I can barely understand a word. Canadian English and Australian English are similar. The same basic language, but different in many ways. I always wanted to write "American" at the top of my paper, not "English."
Films are difficult. Many have regional accents and of course jokes, or even plots that require more than a passing cultural knowledge.