The purpose of this study was to empirically examine the dimensionality of language ability for young children (4-8 years) from prekindergarten to third grade (n = 915), theorizing that measures of vocabulary and grammar ability will represent a unitary trait across these ages, and to determine whether discourse skills represent an additional…

Data from 492 Italian infants (8-18 months) were collected with the parental questionnaire MacArthur Bates Communicative Development Inventories to describe early actions and gestures (A-G) "vocabulary" and its relation with spoken vocabulary in both comprehension and production. A-G were more strongly correlated with word comprehension…