In Pentecostal congregations, prayer is often accompanied by speaking in an unknown tongue, a practice now known as glossolalia. Practitioners of Pentecostal glossolalia may claim that the languages they speak in prayer are real foreign languages, and that the ability to speak those languages spontaneously is a gift of the Holy Spirit. Some people outside of the movement, however, have offered dissenting views. George Barton Cutten suggested that glossolalia was a sign of mental illness. Felicitas Goodman suggested that tongue speakers were under a form of hypnosis. Others suggest that it is a learned behaviour. Some of these views have allegedly been refuted.