In this paper we investigate and discuss optimal educational approaches on relations between Japanese oral proficiency and language behavior in multicultural society in Japan, based on two longitudinal studies (1) Japanese Brazilian students living in a concentrated area A (2007–2012) and (2) Pakistani students living in a scattered area B (2013–2015). In particular, from the point of social participation, we analyzed the importance of language environment as well as use of mother tongues and heritage languages.
In the case of concentrated area A, we found that CLD students’ social participation as bilingual teaching assistants, accelerated both their Japanese and Portuguese oral proficiencies, for example in usage of “noda” for the sustainability and attainability of paragraphs. Meanwhile, in the scattered area B, we observed that participation as ad-hoc Japanese teaching assistants during their trip to Hiroshima, promoted Japanese proficiency, in particular in oral and composition skills.
Based on these findings, in Japan’s developing multicultural society, understanding the importance of promotion of constructing language environment for the CLD students, such as ethnolinguistic vitality (EV) as well as communication network (CN), we foresee students’ participation in the social (learning) environment and its optimization.