This ABC  video demonstrates a classic example of deist Pentecostal delusion.

Scientific perspectives

Neuroscience

In 2006, at the University of Pennsylvania, researchers, under the direction of Andrew Newberg, MD, completed the world's first brain-scan study of a group of Pentecostal Practitioners while they were speaking in tongues. Newberg found that the brain responds very differently than when nuns pray or Buddhists meditate. Several significant findings were identified. First, although the practitioners spoke in a coherent language-like way, activity in the language centers of the brain actually decreased, which raises the question of where the language was coming from. This suggests that the brain contains other unidentified language circuits.

In this form of spiritual practice, Pentecostal practitioners temporarily suspend their system of beliefs (generated by frontal lobe activity, which decreases during glossolalia). This is similar to how creativity works in the brain; we basically enter altered states of consciousness, and this gives us a new perception of the world.

Other differences were found: Pentecostalists maintain a sense of God's otherness, whereas Eastern meditation traditions dissolve the self/other sense. Those practitioners tend to feel "at one" with the universe or God (the parietal lobe activity decreases). The emotional strength of glossolalic experiences also would leave a lasting imprint on the brain. In essence, different forms of prayer and meditation allow for different experiences of the world, reality, and the ultimate nature of God or the universe.

The brain scans also showed a permanent unusual asymmetry in thalamic activity, which was also found in Newberg's scans of nuns and Buddhists. This supports the theory that either intensive prayer permanently alters the brain, or that people with an abnormally functioning thalamus are more prone to having spiritual/religious experiences. It also suggests that intensive focusing on any idea stimulates a series of circuits in the brain that turn the object of contemplation into a physical reality. The study will published in the journal PSYCHIATRY: NEUROIMAGING in the fall of 2006, and is fully described in Newberg's book, WHY WE BELIEVE WHAT WE BELIEVE. Newberg is Associate Professor, Departments of Radiology and Psychiatry, University of Pennsylvania and Staff Physician, Division of Nuclear Medicine, University of Pennsylvania Health System.

Linguistics

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, the United Kingdom, and Brazil all sound quite different from each other, but vaguely resemble the Russian, English, and Portuguese languages, respectively. Many linguists generally regard most glossolalia as lacking any identifiable semantics, syntax, or morphology.http://www.meta-religion.com/Linguistics/Glossolalia/contemporary_linguistic_study.htm

Psychology

The first scientific study of glossolalia was done by psychiatrist Emil Kraepelin as part of his research into the linguistic behaviour of schizophrenic patients. In 1927, G.B. Cutten published his book Speaking with tongues; historically and psychologically considered, which was regarded a standard in medical literature for many years. Like Kraepelin, he linked glossolalia to schizophrenia and hysteria. In 1972, John Kildahl took a different psychological perspective in his book The Psychology of Speaking in Tongues. He stated that glossolalia was not necessarily a symptom of a mental illness and that glossolalists suffer less from stress. He did observe, however, that glossolalists tend to have more need of authority figures and appeared to have had more crises in their lives.

Nicholas Spanos described glossolalia as an acquired ability, for which no real trance is needed (Glossolalia as Learned Behavior: An Experimental Demonstration, 1987). It is also known as a simplex communication.