Glossolalia is the utterance of what appear to be nonsense syllables, sometimes as a form of religious worship (religious glossolalia), and sometimes by the mentally ill. In some Christian traditions (see below), glossolalia is held to be a gift of the Holy Spirit, and therefore the foregoing definition would be strictly incorrect; for them, the defining characteristic of divinely-inspired glossolalia is that it is indeed divinely-inspired language that is, typically, unknown to both speakers and listeners. Christianity is not the only religion that practices or uses glossolalia as a part of worship.
From a linguistic point of view, the syllables that make up instances of glossolalia typically appear to be unpatterned reorganizations of phonemes from the primary language of the person uttering the syllables; thus, the glossolalia of people from Russia, Britain, and Brazil all sound quite different from each other, but vaguely resembling the Russian, English, and Portuguese languages, respectively. Most glossalia is generally regarded by linguists as lacking any identifiable semantics, syntax, or morphology--i.e., nonsense and not language at all.
In Christian religious contexts, glossolalia is known as "speaking in tongues", after verses in the Bible. In the book of Acts, "tongues of fire" are said to have decended upon the heads of the Apostles, giving them the miraculous gift of speaking in languages recognizable to others present as particular foreign languages. Hence, theirs could be described as religious xenoglossia, i.e., miraculously speaking in an actual foreign language that is unknown to the speaker.
Speaking in tongues, or a modern version thereof, is popular, and even central, in the Pentecostal and Charismatic traditions. The belief that the gifts of the Apostles (Acts 2) are present in the modern world is a fundamental point of Pentecostal doctrine. Thus, Pentacostalists and some other religious adherents hold that this religious glossolalia is, at least in some cases, bona fide language inspired by the Holy Spirit, one unknown usually to both the speaker and the listeners. Some other Christians hold that that all, or almost all, modern glossolalia is bogus and neither divinely inspired nor language. It is much more common among Christians to believe that the original instances of glossolalia, as reported in the book of Acts, were bona fide instances of actual human languages.
We need a few good paragraphs about schizophrenic glossolalia...
- Bible 411 on Glossolalia
- The Skeptic's Dictionary on Glossolalia
- Glossolalia, an online book by Rene Noorbergen
- Google search