The role of prematurity and socioeconomic status in the onset of canonical babbling in infants

The onset of canonical babbling (implying production of well-formed syllables) is a landmark event in the development of the capacity for speech, capping a series of vocal stages of the infant's first year of life. Infants who are handicapped with regard to linguistic development are, in some cases, delayed in the onset of speech-like sounds such as canonical syllables. The age of onset of canonical babbling in infants born at risk, either due to prematurity or due to low socioeconomic status (SES) has not been extensively studied. This research, based on a longitudinal investigation of babbling and other motor milestones in term and preterm infants of middle and low SES, indicates that the onset of canonical babbling is robust with regard to such risk factors. Neither preterm infants whose ages were corrected for gestational age, nor infants of low SES were delayed in the onset of canonical babbling. In fact, at corrected ages, the preterm infants appeared to begin canonical babbling earlier than their full-term counterparts. It is suggested that the greater auditory experience of the preterms in this study may account for the early appearance of canonical babbling and hand banging, both of which can be viewed as rhythmic stereotypies that may require auditory feedback for normal development. Other motor milestones studied showed neither delay nor acceleration of onset in the same infants.