GLOSSOLALIA (from the Greek glōssa, "tongue, language," and lalein, "to talk") is a nonordinary speech behavior that is institutionalized as a religious ritual in numerous Western and non-Western religious communities. Its worldwide distribution attests to its antiquity, as does its mention in ancient documents. It is alluded to in the Hebrew scriptures and in the New Testament, as in the well-known narration in the Acts of the Apostles about events on the Day of the Pentecost. There are references to it in the Vedas (c. 1000 BCE), in Patañjali's Yoga Sutras, and in Tibetan Tantric writings. Traces of it can be found in the litanies (dhikrs) of some orders of the Islamic Sufi mystics.

Early ethnographic reports of glossolalia treated it with contempt, calling it "absurd nonsense, gibberish scarce worth recording," while Christian theologians tended to think of it as an exclusively Christian phenomenon, peculiar, according...