I've answered that before, Sue, but I can understand someone not bothering to read the whole of this thread - English, e.g., folk-songs have been handed down and collectors have found them being sung unaccompanied; I'd mentioned Walton's book The Complete Angler, which gives verses and mentions of a song for a fish or two. The problem faced by modern folkies is addressed in the quote from The Penguin Book of English Folk Songs, provided by Snuffy, above - "for those to whom the unaccompanied voice seems naked"; and it's getting worse.
Tanglewood - when classical composers have wished to give a nod to nationalism, they have often turned to the folk music of their nation.
To Don - why should I bother addressing someone who keeps referring to the "ignorance" of another who did get distinctions in anthropology? However, I will say this - yes, some have been into folk for a long time: and their selections/choices may have been good or bad for all that time. Others, with a good background and some good fortune, may quickly work out the way to go.