1.Someone who doesnt write his own material.
2.someone who doesnt sound like Peter Pears.
3.Someone who doesnt sound like either Barry Manilow or George Melly.
4.someone who doesnt use heavy metal type guitar accompaniment.
so style comes in to it,and also material.
what is debatable as regards labelling is how the material was learned.
many feel it has to be learned aurally in an unbroken chain from members of a community.
so where does that leave singers who have learned aurally from you tube,are they traditional singers or are they only traditional singers if they have learned the song from a recording of a source singer such as Phil Tanner,or do they have to learn a song from an existing traditional singer such as Bob Lewis,and are they they then disqualified from being a traditional singer,unless they learned it in his physical presence.