What Irish monks did for the ancient classical texts, a dedicated group of evangelical missionaries may be doing for the world’s disappearing languages. Since 1939, the Global Recordings Network has been spreading the gospel to remote parts of Africa, Asia, the Pacific, and to migrant farm workers in California, people they call “tailenders” because they are the last to be reached by progress. The GRN missionaries believe nothing builds trust like the language of the hearth, so they distribute recordings of Bible stories and Christian teachings in their prospective converts’ own tongues, building hand-cranked cassette players and phonographs to play in . As a happy side effect, GRN, the subject of a documentary showing on PBS’s series “P.O.V.” tonight, has been building what may be the largest archive of dying languages in the world.

Less happy, in the view of the filmmakers, is what evangelism does to the people it reaches. Even the missionaries say that Christianity makes locals more willing to compromise with corporations who come to despoil their lands, and their converts say they were drawn by Western prosperity–cars and town living–as much as Christianity. GRN’s volunteers, after all, are concerned with the fate of souls, not rainforests. The filmmakers are so anxious to signal their disapproval that they begin to burden the film with simplistic critiques, portraying GSN’s efforts—indeed, American Protestantism itself–as “a syncretism of Christianity and technology.” Eventually their overt hostility bogs down a film whose images alone do more to expose the wariness, awe, and desire of the tailenders than any voice-over lecture.