I grew up in the neighborhood of Pfalz, Germany namely Saarland, Germany. And I remember that as a child, my teachers were always trying to get us to speak proper German. They did that by telling us that my local dialect sounds stupid and uneducated. In Saarland, some schools teach french as the first foreign language, which makes it the third language that I learned before I ever learned any English. After having worked in the UK for more than ten years, I now regard my dialect no more stupid than eg the swiss dialect, (a variation on the German language) that is even spoken on their national television. I have worked in Switzerland as well and know from personal experience that even lectures are held in their dialect.
Anyway, I would miss it when local dialects or Scottish, Irish, South African, Australian and so on, disappeared. It adds so much colour (mind the "u") to the language. I have found that "Queens English" is invaluable for an German in Birmingham, Huddersfield or Ashington (all UK), given the fact that you want to communicate. I remember my first day in the UK, when I could not answer the question "Would you like a cup of tea?" because I understood not a single word of it.