And now, the final chapter of this saga - several women volunteered to sing for the service, and we looked over the songs katlaughing sent as well as some native american-derived songs in one of the song books published by Libana, a women's a capella group. Unfortunately, a couple of the women had had a bad experience with singing native american music a few years ago - something about whether they had the proper permission of the Navaho nation to sing Nightway Chant. Anyway, because of that experience, they had a strong aversion to doing any native american music whatsoever. Instead we ended up singing a couple of rounds from the Libana book, and some music written by a member of the congregation. It sounded fine, but I'm disappointed that things turned out that way.
Apparently there's a lot more to native american music than I realized - I had been thinking of it as folk music, but maybe to some people it's sacred music, and improper use of it tantamont to blasphemy (and I thought copyright issues were sticky!). I wouldn't want to offend a guest speaker with music that is inappropriate or presented badly, but I'm disturbed by the fact that some in our group were afraid to sing even a simple native american round. I guess I'd better find the time to talk to local tribes and learn more about this. Thanks for your help, eveyone, especially katlaughing.