Research led by Dr. Pumpki Lei Su from The University of Texas at Dallas has shown that the sounds babies make in their first year of life are not as random as previously thought. The study, published in PLOS ONE, observed that infant vocalizations form three categories of sounds in clusters, indicating that children actively explore their vocal capabilities with or without language input from adults. The results suggest that children engage in vocal play to learn what actions produce certain sounds before beginning to babble.
Furthermore, a study published in the Journal of Autism and Developmental Disorders focused on infants who later received a confirmed diagnosis of autism. The research found that children, whether or not diagnosed with autism, exhibit clustering patterns within vocal categories during their first year of life. The study revealed that babies are not passive recipients of input, but instead engage in spontaneous exploration of sounds. This process of learning to produce sounds appears to be more endogenous and independent than previously understood.
The study utilized a dataset of all-day home recordings from over 300 children, coded by senior author Dr. D. Kimbrough Oller’s team at The University of Memphis. By analyzing more than 15,000 recordings from typically developing infants, researchers identified significant clustering patterns of squeals and growls, showing that infants tend to cluster sounds within one vocal category at a time. The research also demonstrated that the majority of infants showed significant clustering patterns at various ages throughout their first year of life.
Dr. Su has received a grant from the National Institute on Deafness and Other Communication Disorders to study the use of “parentese” in autistic children. Parentese is an exaggerated form of speech typically used by parents with young children, characterized by high-pitched elongated words and singsong diction. The study aims to determine whether parentese facilitates word learning for autistic children compared to a more standard adult-directed register.
Collaborating with researchers from The University of Alabama, The University of Memphis, Case Western Reserve University, and Emory University School of Medicine, Dr. Su’s work sheds light on how infants engage in vocal play during their first year of life. The research challenges the notion that babies are passive in their acquisition of speech and highlights the importance of understanding the early stages of language development in typically developing children and those later diagnosed with autism spectrum disorder. Funding for the research was provided by the National Institutes of Health.