Research Abstract |
Since Gentner's (1982) claim that nouns are universally predominant in children's early vocabulary, a noun bias has been confirmed in English-speaking children, while for Mandarin and Korean a prevalence of verbs has been reported. Explanations point to such language-typological factors as pro-drop, which promotes a verb-focused input. For Italian and Japanese, both pro-drop languages, mixed results are reported. On possible explanation is that pro-drop languages allow for greater individual variation in maternal speech, which in turn results in a range of different vocabulary compositions in individual children. Our results from longitudinal speech data of 4 Japanese-speaking mother-child dyads indicate that the mothers adjusted their speech to their children, and adapted a more noun-focused style. This adjustment occurred to an individually different degree, and appeared to be connected with the children's vocabulary composition. The children whose mothers had a noun-and object-focused speech style (high noun/verb ratio in types, tokens, and isolated word presentation, high frequency of object descriptions) displayed a noun-biased vocabulary, while the children of mothers whose use of nouns and verbs was more balanced, produced a balanced or slightly verb-biased vocabulary. Our results suggest that the individual maternal input plays a more important role in a child's development of a noun bias than the general language type.
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