The idea that folk culture or music does not have outside influences from other cultures is flawed.
for example some of the reels in Irish music, were originally scottish, and one or two were strathspeys or other tempos, the polkas that occur in irish music in 2/4 and england in 4/4 were originally mid european.an example is the jenny lind polka a tune written to celebrate the famous singer, turns up later in ireland as a slide