This study investigated 62 infants by means of a longitudinal study in order to see how maternal verbal responsiveness during infancy and social communication ability of infants affect children’s language ability during both infancy and early childhood. Each measurement was performed as follows infant’s social communication ability at 12 months, vocabulary level at 12-, 15- and 18-months, and early childhood language ability at 42 months. Maternal verbal responsiveness was measured during free play by coding the mother’s verbal responsiveness. Children’s social communication ability at 12 months and vocabulary level at 12, 15, and 18 months were measured using PICS (the Pictorial Infant Communication Scale) and a vocabulary check list (M-B CDI-K), respectively. Positive correlations between maternal verbal responsiveness were found at 12 months and receptive vocabulary level at 12, and 15 months. In addition, infants’ social communication ability and receptive/expressive vocabulary level at 12, 15, 18 months and language ability at 42 months were also positively correlated. However, there was no correlation between maternal verbal responsiveness at 12 months and their language ability at 42 months.
Key words : social communication, verbal responsiveness, language development, longitudinal study