Early Lexical Development in Japanese Children

Abstract

The present paper clarified the composition of early vocabulary in Japanese children through the standardized data of the Japanese MacArthur-Bates Communicative Development Inventories (JCDIs), the longitudinal data, and the cross sectional data. We examined especially the issue of noun and verb dominance in early child language. First, the composition of the first 50 words in JCDIs showed that common nouns had the highest proportion. Second, the opportunity scores of nouns, adjectives, verbs, and closed-class words on JCDIs for 158 Japanese children at 20 months of age showed the noun prevalence, and this result was consistent with the results of seven countries in the study by Bornstein et al. (2004). Third, the longitudinal study of two Japanese children showed noun dominance after vocabulary spurt and verb dominance after the emergence of grammar. Caregiver language was verb dominant. Fourth, 31 Japanese children showed the noun dominance in the book-reading context, but in the toy-playing context, there was a shift away as children developed from single words through the presyntactic stage to the syntactic stage. Caregiver language was verb dominant in a number of respects across development in the toy context, and thus was not closely related to child’s lexical balance. We concluded that children have a conceptual disposition to learn nouns in early lexical development. Finally, we discussed the mechanisms of word learning which evoke noun dominance.