Glossolalia is a term found in ancient mythology as well as modern medical science. It refers to meaningless speech or gibberish. It is derived from the Greek word glossa which means tongue or language and lalein which means speak or babble.
In Christian communities glossolalia is known as "speaking in tongues" and is considered a gift. The practice of speaking in tongues is most prominent in Pentecostal communities where it often forms a routine part of group worship, although some Christians believe it should be a private act. Worshipers who speak in tongues are said to be possessed by the Holy Spirit. Occasionally worshippers experience trance states, temporary amnesia, convulsions or fainting.
The New Testament speaks about how "tongues of fire" were seen above the Apostles — this is believed to be the origin of the practice. Some Christians believe the art of speaking in tongues died with the Apostles and is no longer relevant.
Skeptics argue that the language used while speaking in tongues cannot be independently verified so is more likely an example of group behaviour.
In medical science glossolalia refers to random speech uttered by patients suffering psychosis (such as schizophrenia).