Here's a quote I like from Milan Kundera's The Joke, his first novel, published in 1966:

A folk song is born differently from a formal poem. Poets create in order to express themselves, to say what it is that makes them unique. In the folk song, one does not stand out from the others but joins with them. The folk song grew like a stalactite. Drop by drop enveloping itself in new motifs, in new variants. It was passed from generation to generation, and everyone who sang it added something new to it. Every song had many creators, and all of them modestly disappeared behind their creation.