Influence of Letter Properties on Japanese Hiragana Reading and Writing Acquisition

Abstract

In the present study, we examined the relationship between hiragana reading/writing acquisition and letter properties. For letter properties, we used visual complexity, letter frequency as obtained from our large-scale picture book corpus, and order of appearance in the hiragana 50-sound table. Hiragana reading and writing accuracy rankings were obtained from the dataset of the National Institute of Japanese Language for 4- to 5-year-old toddlers, and the relationships with letter properties were examined. Hiragana reading accuracy rankings significantly correlated with letter frequency in picture books and order of appearance in the hiragana 50-sound table. For hiragana writing, visual complexity significantly correlated, in addition to letter frequency and order of appearance in the hiragana 50-sound table. In further analysis, hiragana letters were divided into three groups based on hiragana reading and writing accuracy rankings. We examined which letter properties can predict hiragana reading and writing performance using ordered logistic regression analysis. Letter frequency significantly predicted both reading and writing performance, whereas visual complexity predicted hiragana writing only. These results imply differential contributions of letter properties for reading and writing, with visual exposure in picture books playing a critical role for reading acquisition, but visual exposure and visual recognition apparently critical for writing acquisition. The present study did not investigate the influence of children's speaking or letters included in their own name, however. Further study is needed to achieve a comprehensive understanding of toddlers' hiragana reading and writing acquisition.