glossolalia

An icon depicting the Theotokos with the apostles filled with the Holy Spirit, indicated by "cloven tongues like as of fire" (Acts 2:3) above their heads People speaking in tongues and in Portuguese during an Evangelical event in Brazil Speaking in tongues, also known as glossolalia, is a phenomenon or practice in which people utter words or speech-like sounds, often thought by believers to be languages unknown to the speaker. One definition used by linguists is the fluid vocalizing of speech-like syllables that lack any readily comprehensible meaning. In some cases, as part of religious practice, some believe it to be a divine language unknown to the speaker. Glossolalia is practiced in Pentecostal and charismatic Christianity, as well as in other religions.

Sometimes a distinction is made between "glossolalia" and "xenolalia", or "xenoglossy", which specifically relates to the belief that the language being spoken is a natural language previously unknown to the speaker.