As a librarian I've been interested in classification issues. A few years ago I looked through some of the old Dewey schedules. We don't have all of them, but the first one that had the class number I wanted was labeled: Volkslieder. I don't rememeber the date, but this was late 19th or early 20th century when an American classification schedule did not even translate the word!

I may be mistaken, but I think of the Germans as almost having invented the concept of 'folk' with the Grimm's work on folk tales & what ever the musicologists were doing. I was under the impression that is sprang from the fact that greater Germany was divided among several states & there was a desire to forge a common German identity. I don't think the people working in the field had any idea that same motive could be as corrupted as it later was by Bismark & Hitler.