Hootennany, sounds like an interesting read. I agree that it is generally accepted that Afro-Americans often sang pieces derived in part from British ballads.

On Child, what he said about ballads in the encyclopaedia article he wrote has been discussed on another thread. Suffice it to say here that he explicitly rejected the idea that ballads were composed or written by what he calls the 'lower orders' of society. But his views on their origins generally seem based upon what has to be guesswork about the social structure of pre-literate societies, so to be taken for what they are: conjectural. Yet in places he states them as if they were proven facts.

An interesting point is that he asserts that rhyme came into use in the 9th century, the age of Alfred the Great and Viking presence in the British Isles.