The only problem I have with folks that attempt to affect a dialect is when they don't take the time to be sure that they are singing, or telling a joke in the appropriate dialect, and getting it fairly close. Like singing the songs, one cannot be lazy or they actually do the opposite of honoring the song. I have heard folks do "Irish" that had little snippets of the North, Dublin, and the West all at once. And all done badly. To me that is lazy on the part of the performer. It seems to me that dialect should be used if it is necessary to the song, and should not be used to try and appear to be something you are not. Done well, as in the example Jed gives for "The Yellow On The Broom", it can be effective. I also reject out of hand the notion that it should never be done.

All the best,

Mick