Bilingual Vocabulary Knowledge and Arrival Age Among Japanese Heritage Language Students at Hoshuukoo

Abstract: This study examines bilingual vocabulary knowledge in relation to arrival age among first language (L1) Japanese students attending hoshuukoo (i.e., supplementary academic schools for Japanese-speaking children) in the United States. It also examines the relationship between L1 Japanese and English as a second language (L2), as motivated by Cummins's (1979, 1991) notion of linguistic interdependence. One hundred and twenty-two high school students ages 15-18 from eight hoshuukoo took Japanese and English vocabulary tests designed by Ono (1989). Students who came to the United States by age 9 or younger were three grades behind in L1 Japanese and were either ahead of or at their U.S. grade level in English. In contrast, those who arrived at age 10 or older were just one grade behind in Japanese and were two to five years behind in English. High vocabulary knowledge in one language was associated with low knowledge in the other, and the negative correlation between L1 and L2 became statistically nonsignificant when arrival age was controlled. Consequently, arrival age remains an important factor in accounting for hoshuukoo students' bilingual vocabulary learning, and the notion of linguistic interdependence must be reexamined in factors in addition to vocabulary knowledge.Key words: arrival age, heritage language learners, hoshuukoo, Japanese-English bilinguals, vocabulary knowledgeAs a result of globalization, an increasing number of school-age Japanese children accompanied by their parents receive formal education overseas. According to the statistics given by the Japanese Ministry of Education, Science, Sports, and Technology (MEXT), the number of ele- mentary and middle school children living abroad for over three months was only 6,662 in 1971, but it has been steadily increasing since then and reached 64,950 in 2012. Roughly speaking, one third of those chil- dren reside in North America (21,280), another one third live in Asia (26,498), one sixth stay in Europe (12,069), and the remaining children reside in other parts of the world (MEXT, 2012, n.p.).The statistics also show substantial differences between regions in the types of educational institutions that children of Japanese as a first language (LI) attend. In North America, it is reported that 45.0% of LI Japanese children attend both local schools and hoshuukoo1-extracurricular supplemental schools that provide academic instruction in Japanese, 53.2% attend local school only, and 1.8% attend full-day Japanese school where students receive academic instruction exclusively in Japanese throughout the week. In Asian countries, in contrast, it is reported that 55.5% attend full-day Japanese school, 41.1% attend local school only, and 3.4% attend hoshu- ukoo. As most hoshuukoo provide only limited hours of instruction during week- ends, students who report that they attend hoshuukoo are most likely to attend local school on weekdays. In other words, more than 98% of LI Japanese children residing in North America receive school instruction mainly in English, their second language (L2),2 and limited academic instruction in their LI if they attend hoshuukoo, whereas a majority of LI Japanese children residing in Asian countries receive school education in Japanese.What does growing up in an L2- dominant environment mean to LI Japanese children in terms of their language develop- ment? What impact does school instruction primarily in the L2 and partially in the LI have on their bilingual development? Do older children experience LI or L2 learning processes similar to those of younger chil- dren? Are children who are proficient in the LI more likely to attain high L2 proficiency than those who are less proficient in the LI? Motivated by these questions, the present study investigates bilingual proficiency among Japanese English-speaking high school students attending a weekend hoshu- ukoo in the United States. More specifically, it examines high-school-age hoshuukoo students' vocabulary knowledge in LI Japanese and L2 English, compared with their native counterparts, and it explores the relationship between the two languages. …