FUJITA, S. , KOBAYASHI, T. , OKUMURA, Y. & HATTORI, T.
NTT Communication Science Laboratories
Given previous evidence that picture-book reading promotes child vocabulary acquisition (e.g., Fletcher & Reese, 2005), it is important to examine an effect of words that appear in picture books on child vocabulary acquisition. However, the effect has not been fully examined due to lack of picture-book corpora. In this study, we constructed a large-scaled corpus of Japanese picture books (N=2,661) to examine a relationship between words in picture books and the age of acquisition (AoA) that was estimated from large-scaled vocabulary-checklist data in Japanese-speaking children (N=1,285). We found that the AoA of a word that represents basic-level category, such as a word \"dog\", show a strong correlation between the total instances of the word in all books (TI) (Spearman's rank correlation: rho=-0.78) and an even stronger correlation between the number of books containing the word (NB) (rho=-0.83). The result suggests that children tend to acquire basic-level nouns that frequently appear in picture books at an earlier age. Moreover, verbs, adjectives and superordinate-level words required higher TI and NB for acquisition compared with basic-level nouns. These findings are discussed in light of previous evidence concerning child vocabulary acquisition from an experimental approach using novel words (e.g., Imai & Haryu, 2007).