Lots of food for thought. I tend to agree with McGrath of Harlow that 'Sumer is Icumen in' is the oldest folk song that is still sung as I've heard someone do it at a folk club - however, I can't remember if it was sung or spoken (does it come with a tune?).Other candidates are of archaeological interest only as they have died out in the oral tradition and are mainly now of scholarly interest only. Still, an interesting subject to while away a few hours on a chilly January night!