Just another thought that I meant to put in the last posting. The idea that one should or should not sing songs in accents other than one's own, or songs from one's own culture would rule out a large percentage of the middle and upper classes, or anyone that uses 'Received Pronuncation' - which is why so many '70s and '80s singers of English rural songs adopted a folky Mummerset accent to cover up their Grammar school or university tones.
    As for American songs we tend to forget, or p'raps haven't even thought about, the fact that what we think of as an American accent is a relatively recent phenomenon. In the gunslinging, trail-riding, river-boating days of the 19th century many people spoke with British or other European accents. There were plenty of first or second generation gunfighters and Marshalls with Lancashire accents, cowboys with Scottish and Cockney accents, Welsh miners, storytellers and farmers on Beech Mountain, North Carolina, speaking an even earlier English, and Irish accents everywhere especially in the army and the police. In the American Civil War there were English adventurers riding with the Confederate cavalry and Irish infantrymen, straight off the ships fighting, singing, and dying for the North. From the 1840s through to the end of the century Nigger Minstrel Shows such as the Christy Minstrels toured the length and breadth of Britain leaving their blackface songs (often sung to Irish tunes) in villages across the country. Norfolk's Sam Larner sang the minstrel song and dance 'Old Bob Ridley' and Alfred Williams collected minstrel songs in Oxfordshire and Wiltshire. Collections of Minstrel songs were published in London from the midde of the 19th century. Some of the finest recordings of early 20th century Irish music were made in America, There are field recordings from California of what most would think of as a southern English dance tune repertoire and the same in Australia. In the 1930s traditional melodeon, concertina and fiddle players, from Australia or America could have sat down in a Suffolk or a Devon pub and played the same sets of tunes, in a very similar style.
The only difference with all of the above and the blinkered folk revival world is that nobody told any of those people that they shouldn't be doing what they were doing, many of them would have sung songs without any inhibitions or looking over their shoulders for the folk police. I've yet to meet a traditional performer who judges you on where you come from, what accent you've got, or whether or not you should be playing that particular instrument or tune. All I've ever met both here in Britain and America are traditional performers who are so steeped in the music and so keen to play or sing it with you and to share the pleasure of the music that they've got no time or inclination to lay down rules and query your right to play with them. If traditional performers can be so open and welcoming how come so many revivalists who claim to love and understand the music are so anally retentive and joyless? Or p'raps I've got it all wrong and I've just been extremely lucky in my dealings with traditional performers, and haven't yet come across the crabby ones. I wonder if Elizabeth Cotton and Leadbelly had any doubts about the young, white, middle-class Seegers learning and playing their music? I doubt they had much more in common with them culturally, and vocally than the love of the music.