There are many, many versions of this song, with many different tunes. Samuel Pepys knew it and referred to it in his diary in 1666 as ‘the little Scottish song Barbara Allen’. There is a good summary of its recording history and some interesting background at Mainly Norfolk.
Jean Ritchie of course sings an Appalachian version. For information about her, see the Wikipedia article here. She is currently 91 and has been known to leave comments on the Mudcat Café website. I see her as perhaps the greatest living Appalachian folk singer.