I think that there is something about the title of the W/C recording ("Common Tongue") that gets at the idea of identity, folk or otherwise. I can't fully put my finger (or foot) on it, especially at 1:46 in the morning, but there is something to the idea that the range of people who recognize/speak/understand/share-a-common-understanding-of a concept comes close to defining the boundaries of the concept. I think part of my discomfort with defining folk mainly in historical terms (which, I know, is a huge over-simplification of this discussion) means that the range of people who relate to the music becomes very small.