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Christian Glossolalia: A Biblical Review of Clinical and Physiological Studies

Joseph W. Bergeron, M.D.

Cyberjournal for Pentecostal-Charismatic Research Volume 23.  July 2016



Glossolalia has been practiced among Christians since the first century AD.  Clinical investigators have sought to describe and understand the phenomena through observation, case reports and investigative studies.  Some have hypothesized that glossolalia arises from underlying psychosocial pathology.  A correlation between Christian glossolalia and psychopathology has not been established, however.  Some studies have suggested a positive correlation between glossolalia and mental health.  Recent studies of cerebral blood flow during glossolalia have provided novel insights into changes of cerebral neuronal activity during glossolalia compared to speech in a known language. Cerebral activity and correlative neuroanatomical function are found to be consistent with biblical doctrines of glossolalia.




Christian Glossolalia, or “speaking in tongues”, has been sporadically practiced through history among Christians dating back to the first century AD since it first occurred on the Day of Pentecost following Jesus’ crucifixion (Acts 2:1-4).[i]Many adherents since the 20th Century have considered it a physical sign of the Baptism in the Holy Spirit promised by Jesus (Acts 1:4-8). Renewed widespread interest in Christian glossolalia developed after the Azusa Street Revival in Los Angeles in 1906 leading to the modern Pentecostal movement.[ii]  In more recent times, glossolalia was further popularized and spread to non-Pentecostal denominations during the Charismatic Renewal of the 1960’s and 1970’s.[iii] Glossolalia is now practiced by millions of Christians in many denominations.[iv]


Words spoken in glossolalia are not learned nor understood by the speaker (I Cor 14:2).  In the first biblical account of glossolalia, Christians spoke in actual foreign languages which were understood by bystanders but unknown to the speakers (Acts 2:6-12).[v]  There are many similar anecdotal reports in modern times of glossolalists being unaware they were speaking in foreign languages.  Although scientific confirmation is wanting, such accounts are too numerous to dismiss the potential validity of such phenomena.  Most, however, practice glossolalia privately as part of their individual prayer discipline without comprehension of what is spoken (I Cor 14:14-15). 


Glossolalia is a culturally atypical behavior, and as such, has not escaped the attention of medical scientists and clinical observers who have sought to understand the phenomena. Hypotheses and theoretical explanations understandably reflect perspectives of the respective disciplines of investigators. Clinical academic literature has predominantly consisted of theoretical explanations of observed behavior, case reports, and linguistic studies.[vi] Investigative studies have been few and studies reporting physiological data related to glossolalia are rare.  Recent neuroimaging techniques offer new and unique insight into brain activity during glossolalia.  For the first time, physiological data correlating with cerebral activity during glossolalia and can be quantified and compared to the biblical doctrines of Christian glossolalia.


Observational Studies


        Clinical analysis and hypotheses regarding the practice of glossolalia often reflect the theoretical predispositions of the researchers.  Carl Jung, for example, considered glossolalia to be contents of unconscious psychic disorder intruding into conscious experience.[vii] Joel Brende and Donald Rinsley suggested that glossolalia are regressive utterances reflecting fixation or impaired psychological development, and as such, individuals having varied psychological disturbances for example borderline personality disorder, were attracted to glossolalia and groups that embraced the practice.[viii] John Castelein suggested that glossolalia may arise from narcissistic personality characteristics and that it actually served as a kind of therapy.[ix]


Linguistic observations have described two types of glossolalic utterances; a formulaic-type characterized by stereotypic and repetitive elements, and an innovative-type characterized by novel and unpredictable chains of speech elements. The study was small and did not seek to explore psychosocial correlates.[x]  Nicholas Spanos hypothesized that glossolalia was a learned and cognitively directed behavior.  He experimented with 60 non-glossolalic subjects by having them listen to recordings of glossolalia and found that study participants were able to learn glossolalia-like utterances with reported fluency.  Spanos felt this was supportive of his learned-behavior hypothesis for glossolalia.[xi]  Contrary to learned-behavior hypotheses, the anthropological observations of Felicitas D. Goodman have noted cross cultural similarities of glossolalic utterance and speculated that those practicing glossolalia experienced dissociative or trance-like states that were similar despite differing cultural milieu.[xii]


Anthony Hempel performed screening evaluations on 148 inmates admitted to a maximum security prison, 18 of whom were identified as glossolalists.  Inmates were accepted as study participants if they believed their ability to speak in tongues was associated with the Holy Spirit or other supernatural entity entering their body.  These inmates were found to have psychiatric diagnoses, either bipolar affective disorder or schizoaffective disorder.[xiii] Crimes were associated with sexual and religious delusions or hallucinations and tended to be motivated by psychosis with hyper-religious thinking.  Hempel suggested that screening inmates as to whether or not they practiced glossolalia might be a useful part of prison intake assessments and aid in identifying inmates at risk for certain kinds of psychiatric comorbidities.[xiv]


Leslie Francis and Susan Jones collected data from 368 adult Christians with the Revised Eysenck Personality Questionnaire and the Myers Briggs Type Indicator.  Charismatic Christians were identified among study participants by the Index of Charismatic Experience questionnaire developed by Francis and Jones.  Those characterized as introverts were equally accepting of the Charismatic experience as those characterized as extroverts.  Those in the Charismatic cohort showed no association with psychosis and showed a decreased tendency to neuroticism.  Charismatic Christians tended to show stable extroversion and increased emotional stability compared to non-Charismatic participants.[xv] In a similar follow up study, Leslie Francis and Susan Robbins studied clergy, surveying 991 male clergy with the Revised Eysenck Personality Questionnaire, along with questions to identify those who practiced of glossolalia.  Similarly, they found no association with glossolalia and psychosis plus a decreased tendency to neuroticism among glossolalia subjects compared to others.  These findings suggested that glossolalia may be associated with improved psychological stability.[xvi]


Physiological Studies


            Roy Reeves reported a case of a 44 year old female who consistently developed left arm shaking with right temporal lobe epileptiform activity on electroencephalogram (EEG) during glossolalia.  The arm shaking consistently developed within 15-30 seconds of initiating glossolalia.  The seizure activity did not spread to other parts of the body and stopped with cessation of glossolalia.  Seizure activity was not reported outside the context of glossolalia in that subject.[xvii]  Michael Persinger reported temporal lobe EEG abnormalities in two subjects, one during transcendental meditation (TM) and in another subject during glossolalia.  The TM practitioner exhibited subclinical seizure activity, namely, EEG abnormalities in the temporal lobe consistent with electrical findings of seizure but without any observable physical signs of seizure. That subject had no specific comments about the meditation experience, only that it had been a meaningful time of meditation.  Persinger recorded EEG studies of two glossolalia subjects one of whom had a normal EEG but the other subject’s EEG recorded temporal lobe spikes during glossolalia.  This EEG finding was also observed during non-glossolalia periods in that subject.  No physical signs of seizure were observed in that subject.  The EEG temporal spikes of the glossolalia subject were different in appearance compared with the subclinical electrical seizure activity observed in the TM subject.[xviii]


            Cerebral blood flow is considered a corollary to neuronal activity.  Single photon computed emission tomography (SPECT) measures regional cerebral blood flow (CBF) by measuring gamma emissions from an injected pharmaceutical agent after it enters the brain.  Anthony Newberg studied practicing glossolalia subjects professing Pentecostal or Charismatic faith traditions and found statistically significant differences between regional CBF during glossolalia compared to when the same subjects were singing in their native language.  Findings during glossolalia included decreased regional CBF in the in the prefrontal cortices, left caudate and left temporal pole.  There were CBF increases in the left superior parietal lobe and right amygdale (See Figure 1).[xix] Interestingly, the decreased frontal and increased superior parietal regional CBF during glossolalia were opposite to what had been previously observed by Newberg in subjects during Tibetan Buddhist meditation.[xx]  Regional CBF changes during meditation were thought to be related to increased thought concentration and an altered sense of self during the practice of meditation which are not characteristic of the practice of glossolalia.




Glossolalia has been observed on a limited basis in non-Christian religious sects.[xxi] Glossolalia-like utterances have also been rarely observed among those with severe mental illness, for example psychotic prison inmates.  Glossolalia, therefore, may be an expressive symptom of psychiatric disturbance in certain contexts. Christian glossolalia, however, is widely practiced by millions of Christians in many denominations, ethnicities and cultures in the context of prayer and worship.  Correlation between psychological disturbance and Christian glossolalia has not been established.  Contrariwise, Christian glossolalia appears to be associated with improved psychological stability and mental health. 


Case reports of EEG abnormalities and partial complex seizure activity in glossolalists are rare and unrepeated observations.  The clinical significance of these case studies is unclear.  Certainly, they do not suggest a corollary to the millions of Christian glossolalists who are without neurological symptoms or pathology.


            SPECT studies of CBF changes of Christians during glossolalia offer new and unique insights into brain activity during glossolalia.  Frontal cortex functions are many and include executive cognitive functions such as judgement, personality traits, learning, memory, reasoning, planning, comprehension and organized speech to name a few.[xxii]  The observed diminished prefrontal regional CBF during glossolalia is consistent with lack of planned or intentional control of speech during glossolalia compared to speech in a known language. Preserved superior parietal regional CBF in Newberg’s subjects was felt to indicate that glossolalia was not associated with a “loss of self” or dissociative mental state such as observed in his Buddhist meditation subjects.  There was shifting asymmetry of Thalamic CBF from singing in a known language to singing in glossolalia, which is of uncertain significance.  Since the Thalamus acts as a relay between cortical and subcortical neurons, Newberg opined that this represented a change between volitional language control and release of cognitive control of language formation.  Increased CBF in the Amygdala and caudate during glossolalia may correlate to increased emotion.


            Christian glossolalia is practiced most widely in personal prayer and worship, and sometimes as a public speech during a church service when accompanied with interpretation into a language understood by the audience.  The most detailed descriptions of the nature and practice of glossolalia in the Bible are provided by the Apostle Paul in his first letter to the church at Corinth. Paul was an avid glossolalist affirming to the Christians at Corinth, “I thank my God that I speak in tongues more than you all” (I Cor 14:18).Paul’s fervent devotion to the practice of glossolalia was essential to the credibility of his instructional letter.  The Corinthian church appears to have had excessively vocal meetings prompting Paul to provide corrective instructions in his letter to them.  He emphasized the need for all persons present to understand what was publically spoken during church services, “Yet in the church I had rather speak five words with my understanding, that by my voice I might teach others also, than ten thousand words in an unknown tongue” (I Cor 14:19).  Here, Paul affirms that he did not understand what he was saying during glossolalia.  The speaker’s lack of comprehension of what is said while speaking in tongues is consistent with Newberg’s findings of relative quiescence of the frontal lobes during glossolalia compared to speech in one’s native tongue.  Even though glossolalia-sounding utterances can be learned, considered by some to support the hypothesis that it is a learned behavior, Newberg’s findings of relative frontal cortex quiescence during Christian glossolalia is inconsistent with a learned-behavior hypothesis for glossolalia.


Paul stated, “…For if I pray in an unknown tongue, my spirit prays, but my understanding [comprehension] is unfruitful. What is it then? I will pray with the spirit, and I will pray with the understanding. I will sing with the spirit, and I will sing with the understanding” (I Cor 14:14-15).  Interestingly, Newberg specifically compared singing in his study participant’s native language with singing in glossolalia and measured regional variations in CBF in the same study participant.  Measured differences of regional blood flow, considered indicators of neuronal activity, correlate with Paul’s personal description of differing cerebral involvement during singing in his known language versus singing in glossolalia.  SPECT images of frontal cortex quiescence during glossolalia are consistent with Paul’s description that glossolalia is not cognitively mediated.


Paul described glossolalia as an uplifting spiritual and emotional practice, “He who speaks in an unknown tongue edifies himself …” (I Cor 14:4).  Here, Paul indicates that glossolalia emotionally or spiritually enriches those who practice it.  Jude appears to have made a correlative statement, “But you, beloved, build yourselves up in your most holy faith. Pray in the Holy Spirit” (Jude 20).  Newberg’s findings of increased regional CBF in the right amygdala are consistent with glossolalia having an emotional component.  The amygdala plays a central role in the complex interactions within the brain associated with emotion.[xxiii]


            Superior parietal regional blood flow was preserved in Newberg’s subjects and consistent with the study participant’s descriptions that glossolalia did not require a trance or altered state of consciousness as some have hypothesized.  Preserved conscious thought and willful determination during glossolalia is also alluded to in Paul’s instructional letter to the Corinthian church.  “If anyone speaks in an unknown tongue, let it be by two, or at the most by three, and each in turn, and let one interpret. But if there is no interpreter, let him remain silent in the church, and let him speak to himself and to God” (I Cor 14: 27-28).  Paul instructed Christians that public speech in glossolalia should be done one person at a time, each in turn during a public worship gathering, and not more than three glossolalia speakers at one meeting.  Furthermore, Paul mandated restraint from glossolalia altogether in a public setting if interpretation were unavailable.  We can conclude from  these statements by the Apostle Paul that even though glossolalia utterances do not arise from cognitive thought, learning, or planned speech, the speaker still retains control of their will and decision making capacity.  According to Paul, loss of self-control does not occur during glossolalia.  This was a major underlying premise for Paul’s directives to correct unordered and excessive glossolalia during worship gatherings in Corinth at that time.




Christian glossolalia is widely practiced by millions of Christians in the context of worship and prayer. Suppositions that glossolalia is generally associated with maladaptive sociological behavior or psychopathology are unsupported.  Rather, the practice of glossolalia may be associated with improved emotional stability and mental health.  Recent SPECT brain imaging studies offer unique and novel insights into the physiological activity of the brain during glossolalia. Biblical doctrines on glossolalia appears consistent with quantified variation of regional cerebral blood flow during glossolalia and correlative functional neuroanatomy. 



[i]Morton Kelsey, “A Peculiar History,” in Tongue Speaking: The History and Meaning of Charismatic Experience, (New York: Crossroads Publishing Co., 1981), 32-68.

[ii]Ibid, “The Pentecostal Churches”, 69-94.

[iii] Ibid, “Tongues in the Traditional Churches”, 95-136

[iv] A 2010 Barna research pole indicated that 10% of adult American Christians practice glossolalia.  There is generational variation among adults ranging from 7-13%.  Glossolalia is most prevalent in the “Boomer” generation at 13%.  (How Different Generations View and Engage with Charismatic and Pentecostal Christianity: 3/29/2010).  A 2012 Pew Research Pole found 73% of the then adult American population of approximately 235 million identified themselves as Christians (“Nones” on the Rise, Pew Research Center,   Based on these data, it can be estimated that approximately 17 million adult American Christians actively practice glossolalia. This may underestimate the prevalence of adult Americans who have at some point spoken in tongues.  In another Barna survey, 36% of American adults (approximately 80 million adults) accept the designation of Charismatic or Pentecostal and stated they believed in Charismatic doctrines which included speaking in tongues (Is American Christianity Turning Charismatic? Jan 7 2008). Barna survey references were retrieved from the Barna Group website,

[v]The term Xenoglossiais sometimes used when a foreign language is unknowingly spoken during glossolalia.  The term is a contraction of the Greek words, ξένος "foreigner"and γλῶσσα “tongue” or “language”.  Glossolalia is a non-specific term referring to spoken language in general and is a contraction of the Greed words γλῶσσα “tongue” or “language” and λαλέω “talk” or “speak”.  Neither term is found in the New Testament.  The term glossolalia is attributed to Frederic Farrar and first used in 1879 (Oxford English Dictionary, 2nd ed. 1989).

[vi]A comprehensive medical literature search was performed in MEDLINE/PubMed focused on the subject of glossolalia. Citations for additional articles and books were also extracted from those references.  Altogether, these along with biblical texts formed the basis for this review.  Biblical quotations are from the Modern English Version.

[vii]Carl G. Jung, Psychology and Religion: West and East, 2nd ed., trans. R.F.C. Hull (Princeton: Princeton University Press, 1969), 284 fn 51.

[viii] Joel Brende and Donald Rinsley, “Borderline disorder, Altered States of Consciousness, and Glossolalia,” Journal of the American Academy of Psychoanalysis, Vol 7, No. 2, (1979): 165-188.

[ix] John Castelein, “Glossolalia and the Psychology of the Self and narcissism,” Journal of Religion and Health, Vol 23, No. 1 (1984): 47-62.

[x] H.A. Osser, P.F. Ostwald, B. MacWhinney, and R.L. Casey, “Glossolalic Speech from a Psycholinguistic Perspective,” Journal of Psycholinguistic Research, Vol 2 (1973): 9-19.

[xi] Nicholas Spanos, Wendy Cross, Mark Lepage, and Marjorie Coristine, “Glossolalia as Learned Behavior: An Experimental Demonstration,” Journal of Abnormal Psychology, Vol 95, No. 1 (1986) 21-23.

[xii]Felicitas D. Goodman, “Glossolalia: Speaking in Tongues in Four Cultural Settings,” Confinia Psychiatrica, Vol 12 (1969): 113-129.

[xiii]Having in the past worked as a physician in a prison, on rare occasion I have observed inmates speak in glossolalia-like utterances. My clinical observations were similar to Hempel’s findings. Those I observed had psychiatric disorders associated with delusions and hallucinations. Glossolalic utterances were intermittent with confabulatory speech characterized by disorganized thought and had both in religious and non-religious content.  It must be recognized that prison inmate cohorts with psychiatric disorders are highly select population samplings characterized by antisocial behavior, often with severe and poorly controlled mental illnesses.

[xiv] Anthony G. Hempel, et al., “Fiery Tongues and Mystical Motivations: Glossolalia in a Forensic Population is Associated with Mania and Sexual/Religious Delusions,” Journal of Forensic Sciences, Vol 47 No 2 (2002) 305-312.

[xv] Leslie J. Francis and Susan H. Jones, “Personality and Charismatic Experience among Adult Christians”, Pastoral Psychology, Vol 45, No. 6 (1997) 421-428.

[xvi] Leslie J. Francis and Mandy Robbins, “Personality and Glossolalia: A Study Among Male Evangelical Clergy,” Pastoral Psychology, Vol 51, No 5, (2003) 391-396.

[xvii] Roy R. Reeves, Samet Kose, and Abuhuziefa Abubakr, “Temporal Lobe Discharges and Glossolalia”, Neurocase: The Neural Basis of Cognition, 20:2 (2014) 236-40.

[xviii] Michael A. Persinger, “Striking EEG Profiles from Single Episodes of Glossolalia and Transcendental Meditation”, Perceptual and Motor Skills, 58 (1984) 127-133.

[xix] Anthony B. Newberg, et al., “The Measurement of regional cerebral blood flow during glossolalia: A preliminary SPECT study”, Psychiatry Research: Neuroimaging, 148 (2006) 67-71.

[xx] Anthony Newberg, et al., “The measurement of regional cerebral blood flow during the complex cognitive task of meditation: a preliminary SPECT study”, Psychiatry Research: Neuroimaging, 106 (2001) 113-122.

[xxi] Glossolalia-like behaviors, even xenoglossia (speaking a foreign language), have been observed in ritual cult activity among shamans, voodoo practices and Buddhist monks among others.  It is noteworthy that observations of non-Christian glossolalia are often accompanied by intoxication and dissociative or altered states of consciousness.  Xenoglossic utterances in this context may or may not be religious in nature and may include profanities. (George J. Jennings, “An Ethnological Study of Glossalalia”, Journal of the American Scientific Affiliation, Vol 20 (1968) 5-16.).  For this reason, the term Christian Glossolia is used to distinguish glossolalia practices among neo-Pentecostal and Charismatic Christians from those in non-Christian religious and cultural settings.

[xxii]Hal Blumenfeld, Neuroanatomy through Clinical Cases, 2nd ed. (Sunderland: Sinaurer Associates, Inc. Press, 2010) 906-913.

[xxiii] Blumenfeld, Neuroanatomy through Clinical Cases, 845.

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