Speaking in tongues, also known as glossolalia, is an activity 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.[1] Glossolalia is practiced in Pentecostal and charismatic Christianity,[2][3] as well as in other religions.[4][5]
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.[6]
... would prove influential on the development of black Pentecostalism in the early twentieth century, as glossolalia, or speaking in tongues, would be understood as a third work of grace following Holiness and receipt of the Holy Spirit.
While in Houston, Texas, where he had moved his headquarters, Parham came into contact with William Seymour (1870–1922), an African-American Baptist-Holiness preacher. Seymour took from Parham the teaching that the baptism of the Holy Spirit was not the blessing of sanctification but rather a third work of grace that was accompanied by the experience of tongues
There is scarcely to be found an example of "speaking in tongues" in any even nominally Christian context for over 1,600 years after the time of Paul...and yet this "gift" is possessed by numerous shamans and witch doctors of primitive religions, as well as by modern spritistics mediums and the demonically possessed.