Trad song to art song is a very old tradition in itself of course, going back centuries in England, e.g.

For what it's worth, I introduce the tune with tenor recorder, then either sing unaccompanied or double the melody with keys but, as above, I also enjoy hearing those classically trained adding embellishment and a different style that Sandman mentions.

As for "fiddle playing", most folkies nowadays are playing the Italian fiddle/violin but there are many different fiddles from many different nations.

And going back to the books I had to analyse at school, in order to pass exams, could be fun, as JB suggests...