Well for a start whether it is intrumental or not is beside the point. If a tune or song is just composed but is regarded as being traditional then it is being regarded as traditional because of what it sounds like not because of it being written by anon and passed down through the generations. More importantly though Anne you are simply wrong in your assertion that all the composers in the run for awards compose only tunes. They don't and some could easily fall into the singer-songwriter more pop tradition. Re two examples below of those in line for awards taken from the MG Alba Scot Trad Awards site also posted below


https://soundcloud.com/abadgeoffriendship/sorren-maclean-rows-rows-of-3/s-XHiR4?in=folk-radio-uk/sets/scots-trad-music-awards-20

https://soundcloud.com/folk-radio-uk/ross-ainslie-dreaming-daisy/s-XHiR4?in=folk-radio-uk/sets/scots-trad-music-awards-2015



http://www.folkradio.co.uk/2015/11/mg-alba-scots-trad-music-awards-album-of-the-year/