Excerpt of John Ramsay's YouTube comments:

"The 12 year old child of American contra dance inspirator, Dudley Laufman, suggested the Petronella turn dance choreography for the Shaker tune, Simple Gifts, to Pat Shaw when he was in the United States in 1975. Pat shared his choreography with the Berea Country Dancers when he spent two weeks in Berea later that fall. We made a few changes. Here is the 1993 Country Dancer Troupe dancing it in El Salvador. My niece, Jennifer, added additional verses. ..."

If Jennifer did write them, she did it well before 1993 (maybe in 1975? hard to tell from his comments exactly when the additional verses were added); I learned those verses in ~1981 when I lived in Kansas City (or possibly was still at University of Kansas in Lawrence) Kansas, from a friend (a brilliant autoharpist named Karen Mueller, in case anyone reading this knows her; last I knew, she was living in the Minneapolis/St Paul area) whose group performed this song. BTW, as this group performed it, there was one more verse, which -- unfortunately -- I no longer remember.

I always wondered where they got these verses from, but didn't manage to find out; would love to, though, so that I could track down that other verse as well...