Parents' child-directed communication and child language development: a longitudinal study with Italian toddlers.

The present study focuses on the characteristics of parental child-directed communication and its relationship with child language development. For this purpose, thirty-six toddlers (18 males and 18 females) and their parents were observed in a laboratory during triadic free play at ages 1 ; 3 and 1 ; 9. The characteristics of the maternal and paternal child-directed language (characteristics of communicative functions and lexicon as reported in psycholinguistic norms for Italian language) were coded during free play. Child language development was assessed during free play and at ages 2 ; 6 and 3 ; 0 using the Italian version of the MacArthur-Bates Communicative Development Inventory (2 ; 6) and the revised Peabody Picture Vocabulary Test (PPVT-R) (3 ; 0). Data analysis indicated differences between mothers and fathers in the quantitative characteristics of communicative functions and language, such as the mean length of utterances (MLU), and the number of tokens and types. Mothers also produced the more frequent nouns in the child lexicon. There emerged a relation between the characteristics of parental child-directed language and child language development.