Some of us are posting spirituals in the dialect in which they were first written down, but anyone who tries to sing 19th Century dialect or vernacular, I think, is bound to get it wrong. The original is there for the record and because it may give the potential user some feel for the song that is not evident from a modern transcription. I agree with Geoff the Duck on this. On the other hand, if the vernacular is current and the singer knows it, excellent! The Scots have preserved much of their language but for others, like Susan, if they were not raised in the tongue, they can approximate and do their best. If the feeling and the expression is there, the mistakes are forgiven.