[lordnacho]

This is a good point. When I was in Switzerland they had a guy from Muothathal on TV. TV decided to subtitle him. I thought Swiss German was weird, but this fellow seemed to be speaking a completely different language, to my beginner ear.

The thing is though, you can ask people to speak High German instead of mundart, eg at meetings. They admit it's different enough to warrant explicit statement.

You can't be telling your Liverpudlian or Brummie to speak the Queen's English, that would be rude.