In response to a couple of points raised by this question and attached threads.

Sinead O'Connor has a particular style of delivery which doesn't suit all songs in very much the same way that many traditional singers make poor attempts at broadening their repetoire by singing ill chosen songs. I have heard her sing meltingly moving renditions of traditional material as well as an occasional unaccompanied renditions of her her own self penned material. She recorded her song "In This Heart" on her Universal Mother album a few years ago and I was so enchanted by the song that it is the title track off my recent album.

The second point that I would like to make concerns the issue of "classical sings traditional".

There are a number of performers both musicians and singers who were initially trained in classical techniqiues but who have moved on into the tradition. Most of these performers, myself included, would say that some knowledge of style and discipline can actually enhance a "traditional" performance. Certainly in the case of singers, it does help to have an insight into projection, posture, breating techniques and pronounciation as it helps with the songs interpretation and the ability for an audience to actually understand the words.

many of us were in fact attracted to traditional song because of our earlier experiences with classical folk song arrangements and people like Britten, V-Williams and Elgar ought be congratulated for their contribution.