A comparison of the transition from first words to grammar in English and Italian

Cross-linguistic similarities and differences in early lexical and grammati cal development are reported for IOOI English-speaking children and 386 Ita lian-speaking children between 1;6 and 2;6. Parents completed the English o r Italian versions of the MacArthur Communicative Development Inventory: Wo rds and Sentences, a parent report instrument that provides information abo ut vocabulary size, vocabulary composition and grammatical complexity acros s this age range. The onset and subsequent growth of nouns, predicates, fun ction words and social terms proved to be quite similar in both languages. No support was found for the prediction that verbs would emerge earlier in Italian, although Italians did produce a higher proportion of social terms, and there were small but intriguing differences in the shape of the growth curve for grammatical function words. A strikingly similar nonlinear relat ionship between grammatical complexity and vocabulary size was observed in both languages, and examination of the order in which function words are ac quired also yielded more similarities than differences. However, a comparis on of the longest sentences reported for a subset of children demonstrates large cross-linguistic differences in the amount of morphology that has bee n acquired in children matched for vocabulary size. Discussion revolves aro und the interplay between language-specific variations in the input to youn g children, and universal cognitive and social constraints on language deve lopment.