Here is the wonderful Emily Smith, who I heard last week at the Edmonton Folk Music Festival, singing ‘Twa Sisters’.
Interestingly enough, I first heard this song in its North American mountain version, sung as ‘O the Wind and Rain’, performed by Crooked Still. This is obviously an earlier version of the same song. Contemplator tells us that ‘Twa Sisters first appears on a broadside in 1656 as The Miller and the King’s Daughter. Variants and alternate titles include: The Cruel Sister, The Bonnie Milldams of Binnorie, The Bonny Bows o’ London, Binnorie and Sister, Dear Sister. Child has 21 versions of lyrics for the tune. The ballad also appears in Scandinavia.’
Emily Smith is both a songwriter and a collector and interpreter of traditional songs, and she and her husband Jamie McClellan have also produced a CD of songs based on lyrics by Robbie Burns. Wikipedia gives some basic information about her, and her website is here.