Hi nan!

I love your bread.

One truly remarkable thing about folk song is that, the further back one goes, the less certain one can be about origin. Surviving sources are not necessarily the original souce. I would think Barbara Allen to be Scots but it's been known in England for many centuries, likewise the USA, Canada and the rest of the English speaking world. As George tells you, the song is well known in Ireland. My recollection is that the story was so compelling that the ballad also entered into the Irish Gaelic tradition.

I have a version from my father that I like to sing with Liam's Sister-in-Law.

I think Rick gave you good answers right away. Rick's a sharp guy.

All the best, Dan