Taken from an article by Dr. Carolyn Leaf’s blog, author of Switch on Your Brain

[Speaking in tongues] Glossolalia been practiced throughout history. Glossolalia experienced a popular resurgence at the beginning of the 20th century through the Azusa Street Revival which started the Pentecostal Movement. As a result of the Azusa Street Revival and subsequent Charismatic Renewal in the 1960s, it has been estimated that about 600 million Christians worldwide believe in or practice Glossolalia [1]. In this brief outline we will examine the effect of Glossolalia on the brain and health in general.

In 2006 Dr. Andrew Newberg at the University of Pennsylvania, using single-photon emission computerized tomography (SPECT), found that the frontal lobe of individuals who spoke in tongues was less active [2]. This brain profile was in contrast to Franciscan nuns in contemplative prayer and Buddhist monks in meditation, in which frontal lobe activity is increased. Since the frontal lobe activity is increased when we are focused on what we are saying, this finding confirms self-reports of what people who spoke in tongues experienced, implying that the words spoken in Glossolalia originate from a source other than the mind of the individual speaking in tongues.

In a 2011 report on a study examining 52 Pentecostals, Dr. Christopher Lynn found that speaking in tongues may actually reduce biological stress as indicated by examining two bio-markers of stress-cortisol and alpha amylase [3]. Additionally, in a study among nearly 1,000 evangelical Christians in England, speaking in tongues was associated with increased emotional stability [4].

 References:
(1) Pentecostal Movement Celebrates Humble Roots’, The Washington Post, 15 April 2006.-

(2) The measurement of regional cerebral blood flow during glossolalia: a preliminary SPECT study.2006 Nov 22;148(1):67-71.Newberg AB1, Wintering NA, Morgan D, Psychiatry Res.(2011) CD Lyn-

(3) Glossolalia is associated with differences in biomarkers of stress and arousal among Apostolic Pentecostals, JJ Paris, CA Frye, LM Schell Religion, Brain & Behavior 1 (3), 173-191-

(4) Leslie J. Francis, and Mandy Robbins. “Personality and Glossolalia: A Study among Male Evangelical Clergy.” Pastoral Psychology 51 (2003): 391–96-

(5) ABC Nightline