It would be worth pointing out to those who are not aware that Brian has fairly recently conducted extensive research into Sharp as part of his project Sharp's Appalachian Harvest in which he worked with Jeff Davis. The result was a delightful multimedia show which we were able to present to an enthusiastic capacity crowd at the 2013 Lewes Folk Festival along with an excellent CD.
Funnily enough, the song that really remains in my mind most from the album and the show is a version of Barbara Allen that Sharp collected from an old African-American woman who, I seem to remember without going back to the album notes. was born a slave. The tune has a slightly bluesy quality. Sharp noted only the tune and a couple of verses and Brian reconstructed the words from other sources - but has come up with a really worthwhile version.
It is known that the slaves were strongly forbidden to communicate in their own African languages and who were removed from their own musical cultures were encouraged to adopt the tunes and songs of their slave owners. I wonder if Cecil Sharp had been aware of this, if he would have tried to seek English songs amongst black ex-slaves. He was not above working with outcast groups. His interactions with English gypsies when collecting from them seem to have been mutually enjoyable.

This all reminds me of seeing the Carolina Chocolate Drops on their first British tour. This black group were researching and performing the neglected black repertoire of their state from the early part of the 20th century, My most vivid memory was when Rhiannon Giddens stood up and said that where she was brought up, a lot of the plantations had been owned by Gaelic-speaking Scots and that she was going to sing unaccompanied a song in Gaelic that was collected from an old black woman. What??? A friend of mine, a Gaelic-speaking fiddle player was in the audience and I made a bee-line for him afterwards. "What was her accent like?" I asked. "Pretty damn good!" was his reply.