SA's remark "This is one of the reasons I take issue with the 1954 Definition because it doesn't go into the musical form that defines the songs " is ludicrous to me. Folk music if it anything is created within a culture and helps define that culture, by community choice (a la 1954 definition basically). How can it have a defined "form"? Scat Tester in Susex played his music one way, Black Umfolosi did it their way, Mongloian goatherds do it their way. How could they possibly come up with a common form? Don't be silly.
Woody Guthrie used an American form. I play NW English tunes in the way I learnt them in the NW of England. How could the 1954 defintion define those forms? The people who made the (very useful) definition probably hadn't heard any Cumbrian merry neet singers. Why should they be familiar with the "form"?