Preterm Infants Produce Language-like Sounds As Soon As They Can Breathe Independently

Groundbreaking Research on the Origin of Language: Precursors to Language in Preterm Infants Still in Neonatal Intensive Care

October 18, 2019 - A paper just published in Scientific Reports shows that infants born prematurely and still in neonatal intensive care two months before their due dates produce abundant speech-like vocalizations, early precursors to speech. These infants, breathing on their own after having been intubated to make breathing possible since birth, produced hundreds of speech-like vocalizations every day as soon as they could breathe independently. The article forms the basis for a new conception about the origin of language: that humans innately engage, as soon as they can breathe on their own, in active vocal exploration that starts down the path toward language. Flexible vocalization in early infancy is necessary for all subsequent developments required by language.

“The result is remarkable, given it is widely believed in pediatrics, developmental psychology, anthropology and primatology that human infants develop speech-like vocalizations from cry,” said the paper’s author, Dr. D. Kimbrough Oller, professor in Communication Sciences and Disorders and Plough Chair of Excellence at the University of Memphis. “However, the study shows that even in preemies recorded at 32 weeks gestational age, the rate of speech-like vocalizations is hundreds per day, while crying was found to occur at less than one-tenth that rate. The study reports longitudinal data from full-term infants from the first month through the end of the first year, demonstrating that speech-like vocalizations outnumbered cries throughout that time by a factor of about five.”

The work is a collaboration of the University of Memphis and the Women and Infants Hospital of Rhode Island (WIHRI) of Alpert Medical School of Brown University, and is based on random sampling and human coding of all-day recordings of infants in the hospital and at home. Other members of the UofM team include Dr. Dale Bowman, associate professor in Mathematical Sciences, and Dr. Eugene Buder, associate professor in the School of Communications Sciences and Disorders. The Brown University team is led by Dr. Betty Vohr, professor of pediatrics with the Alpert Medical School and medical director of the Neonatal Follow-up Clinic Program in the Department of Pediatrics.  

 Prior work on early vocalizations of preterm infants in the NICU at Brown identified that exposure to parental talk was a significantly stronger predictor of infant vocalizations at 32 weeks and conversational turns at 32 and 36 weeks than language from other adults. In addition, child vocalizations per hour and conversation turns per hour were both correlated with their expressive communication scores at 18 months. Researchers continue to learn more about the critical importance of very early vocalization/language development of infants.

Scientific Reports is an open access, scientific mega journal that publishes original research from across all areas of the natural and clinical sciences with a focus to assess the scientific validity of a submitted paper. With a strong global influence, the highly respected journal is the 11th most cited journal in the world and has a five-year impact factor of 4.5. The published study was released on its website Oct. 14. 

Oller serves as an external faculty member of the Konrad Lorenz Institute for Evolution and Cognition Research in Klosterneuburg, Austria, an affiliate of the Institute for Intelligent Systems (IIS) at the UofM and a member of the Scientific Advisory Board of the LENA Research Foundation of Boulder, Colo. His research focuses on vocal development and acquisition of the spoken language and has appeared in more than 230 articles and books addressing infant vocalizations, early speech production, multilingualism and evolution of language.

For more information on the study, contact Oller at koller@memphis.edu or Vohr at BVohr@WIHRI.org.