Effects of Mora Deletion, Nonword Repetition, Rapid Naming, and Visual Search Performance on Beginning Reading in Japanese

Annals of Dyslexia, Jun 2005 by Kobayashi, Maya Shiho, Haynes, Charles W, Macaruso, Paul, Hook, Pamela E, Kato, Junko

This study examined the extent to which mora deletion (phonological analysis), nonword repetition (phonological memory), rapid automatized naming (RAN), and visual search abilities predict reading in Japanese kindergartners and first graders. Analogous abilities have been identified as important predictors of reading skills in alphabetic languages like English. In contrast to English, which is based on grapheme-phoneme relationships, the primary components of Japanese orthography are two syllabaries-hiragana and katakana (collectively termed "kana")-and a system of morphosyllabic symbols (kanji). Three RAN tasks (numbers, objects, syllabary symbols [hiragana]) were used with kindergartners, with an additional kanji RAN task included for first graders. Reading measures included accuracy and speed of passage reading for kindergartners and first graders, and reading comprehension for first graders. In kindergartners, hiragana RAN and number RAN were the only significant predictors of reading accuracy and speed. In first graders, kanji RAN and hiragana RAN predicted reading speed, whereas accuracy was predicted by mora deletion. Reading comprehension was predicted by kanji RAN, mora deletion, and nonword repetition. Although number RAN did not contribute unique variance to any reading measure, it correlated highly with kanji RAN. Implications of these findings for research and practice are discussed.

Key Words: Japanese kana, mora deletion, phonological awareness, rapid naming, reading

INTRODUCTION

This study examined relationships between reading skills and mora deletion (phonological analysis), nonword repetition (phonological memory), rapid automatized naming (RAN), and visual search abilities in Japanese kindergartners and first graders. Generically similar variables have been identified as important in the acquisition of word recognition, fluency, and reading comprehension in alphabetic languages like English (Badian, 1994,1995,1998; Cornwall, 1992; Meyer, Wood, Hart, & Felton, 1998a; Scarborough, 1998). In contrast to the English alphabetic system, which is based on grapheme-phoneme relationships, the primary components of Japanese orthography are two syllabaries: hiragana and katakana (collectively termed "kana"), which include approximately 51 characters each (see Kess & Miyamoto, 1999, for a review). While Japan Educational Ministry guidelines formally require hiragana instruction in first grade, hiragana is typically introduced at home, and in the first and second year of kindergarten. Hiragana symbols are used to represent high-frequency words of Japanese origin, while katakana symbols are taught later (in first grade) and are primarily used to represent foreign words and foreign names. Japanese orthography also contains a system of ideographs (kanji) that are systematically introduced, with approximately 80 characters taught by the end of first grade and about 1,000 by the end of sixth grade. Most texts incorporate both kana and kanji systems. Spoken Japanese is a CV syllable- and morabased language, with mora comprising intrasyllabic units of timing and rhythm (Leong & Tamaoka, 1998). In some words, the syllable and mora units are the same; for example, the word "umi" (sea) has two syllables and two morae. In contrast, the word "kenka" (quarrel) has two syllables and three morae because the first syllable (ken-) has two morae, a CV plus a nasal coda (Akita & Hatano, 1999, p. 214). Each Japanese syllabary character generally represents one or two mora, creating a largely transparent, syllable-based orthography (for discussions of Japanese syllabic and moraic structures, see Leong, Nitta, & Yamada, 2003; Tamaoka & Terao, 2004). Kanji characters, on the other hand, are ideographic, and often have several pronunciations and multiple meanings.

Differences in transparency of written language have been suggested to lead to divergent patterns of reading acquisition and reading disabilities (Bruck, Genesee, & Caravolas, 1997). For instance, Wydell and Butterworth (1999) proposed a "hypothesis of granularity and transparency," which suggests that any language where sound-symbol correspondence is regular or transparent-such as kana characters-or any language whose orthographic units represent sounds at the word level-such as kanji characters-will produce a lower incidence of reading difficulties related to phonological analysis. An assessment of Japanese early readers with selected phonological and visual processing measures could provide insights into the key factors contributing to their reading fluency and comprehension skills.

PHONOLOGICAL ANALYSIS

Phonological analysis is the ability to analyze the sound structure of one's oral language for the purposes of processing written language. In English, phonological analysis is typically assessed with tasks such as rhyming, segmentation, and deletion (Torgesen, Wagner, & Rashotte, 1994; Wagner, Torgesen, & Rashotte, 1999). English-speaking children first develop awareness of word length, then syllables in words. Eventually, their awareness progresses to onset (e.g., /b/ in /bat/) and rime (e.g., /at/ in /bat/), and finally to phonemes within syllables by around age 6 (Wagner et al., 1999).