The Early Acquisition of Speech Communication*

Speech communication problems in two year olds are often thought to originate from previous deviant mother-infant interaction, especially when physical or mental causes for the problems are absent. This study attempts to find a basis for this idea. Split-screen monthly video-recordings of two normal mother-girl pairs were made in naturalistic home settings. Their vocal and behavioural development is described by means of a multi­ channel ethological method. Mother and infant are seen as a unique dynamic sensori­ motor system exchanging movements that selectively acquire communicative meanings. Three characteristics of human communication systems are studied: visual and auditory intersubjective tuning, transmission of intentions, and vocal turntaking by the mother upon speech motor landmarks of the infant. The two pairs differed in their interaction styles during the first six months already, explaining further developmental processes. At the age of two one girl started a speech therapy period of about three years, the other girl was a precocious talker. Evaluation of interactions at risk is suggested and discussed.