"Glossolalia" is the most commonly accepted term for "speaking in tongues." It comes from the Greek words meaning "tongues" or "languages," and "to speak." Although not exclusively, "speaking in tongues" is primarily practiced by Pentecostal Christians. Glossolalia is the "prayer language" of Pentecostal churches. Some Christians who speak in tongues believe they are speaking in an existing language. Most believe they are uttering a heavenly tongue. Some Pentecostal denominations teach that speaking in tongues is the initial evidence of the Baptism in the Holy Spirit.
Although confusing even for some believers who practice speaking in tongues, many Pentecostal denominations teach three distinctions or types of "speaking in tongues:"
- Tongues as a supernatural outpouring and sign to unbelievers (Acts 2:11).
- Tongues for the strengthening of the church - requires an interpretation (1 Corinthians 14:27).
- Tongues as a private prayer language (Romans 8:26).