"A Conjoining of Ancient Song" by Willie Ruff and Gretchen Berland, from the Yale Institute of Sacred Music.
From the official write-up:
The renowned jazz musician and ethnomusicologist Willie Ruff began his journey began several years ago, when he followed up on his friend Dizzy Gillespie’s claim that some remote African American congregations in the Deep South sang hymns in Gaelic, according to Ruff’s website. Consulting The Massachusetts Bay Colony Psalm Book from 1640 in Yale’s Beinecke Rare Book & Manuscript Library, he found that the form, in which one church member calls out the first line of a Psalm and the rest of the congregation continues to chant the text in unison, had been a common worship practice in Colonial America. Pursuing the inquiry, Ruff made the startling discovery that this call-and-response service, chanted by descendants of African slaves in the American South and by white congregations in remote churches of Appalachia, was actually still intoned in Gaelic in its original form in Scotland’s remote and culturally isolated Outer Hebrides.
In 2005, he organized an international conference at Yale, bringing together a few of the almost extinct congregations still practicing the ancient line-singing tradition. The Free Church Psalm Singers of the Isle of Lewis, Scotland; the Indian Bottom Old Regular Baptists of southeastern Kentucky; and the Sipsey River Primitive Baptist Association of Eutaw, Alabama, came to perform a shared service that had adapted over generations to their diverse idioms. In the course of that conference, he learned that the tradition extended to the Muskogee Creeks in Oklahoma as well, and two years later, Ruff, who traces his own lineage back to the crossroads of races and cultures represented in the unusual custom, organized a second conference at Yale to gather Native American, African American and Appalachian line-singers together for the first time.
The 30-minute documentary A Conjoining of Ancient Song is the story of Willie Ruff’s journey connecting Gaelic psalm singing and American Music.