Hey Sharyn, as a Scot's lass who's trying to sing bluegrass, please, please keep on singing the auld Scot's sangs. It's important that they're heard, whether it's by Scots or any other foreign national. Before I came to live here, we used to frequent an Indian restaurant in which the owner (Indian, of course)would sing Scots songs. Nobody took offence!
I truly believe that if it wasn't for Americans and Canadians, our old songs would be even more forgotten than they already are.
By the way, try the Complete Songs of Robert Burns series from Linn Records (linnproducts.com). Just pure dead brilliant, so it is. The singers are fabulous and anyone wanting to sing Scots should listen to them because they sing the way Scottish folk music is suppose to be sung - none of your operatics there.