Previous research shows that monolingual Japanese and Brazilian Portuguese listeners perceive illusory vowels (/u/ and /i/, respectively) within illegal sequences of consonants. Here, several populations of Japanese-Brazilian bilinguals are tested, using an explicit vowel identification task (experiment 1), and an implicit categorization and sequence recall task (experiment 2). Overall, second-generation immigrants, who first acquired Japanese at home and Brazilian during childhood (after age 4) showed a typical Brazilian pattern of result (and so did simultaneous bilinguals, who were exposed to both languages from birth on). In contrast, late bilinguals, who acquired their second language in adulthood, exhibited a pattern corresponding to their native language. In addition, an influence of the second language was observed in the explicit task of Exp. 1, but not in the implicit task used in Exp. 2, suggesting that second language experience affects mostly explicit or metalinguistic skills. These results are compared to other studies of phonological representations in adopted children or immigrants, and discussed in relation to the role of age of acquisition and sociolinguistic factors.
REFERENCES
Since we tested successive generations of Japanese immigrants in Brazil, and that Japanese immigration in Brazil was fairly limited historically, it was not technically possible to match the age across groups. However, given that our task was not loaded in executive functions and was not speeded, there is no reason to expect differences in performance as a function of age. Even if it did, our analysis did not focus on absolute percentages, but rather on the difference between /i/ and /u/ responses, which then should be relatively invariant with age.
To compare with the analysis ran in experiment 1, we computed a correlation between prior exposure to Japanese and the ebna/ebina versus ebna/ebuna difference score, for the students of Japanese group [, , , and , , for the categorization and sequence recall tasks, respectively]. Contrary to experiment 1, it was not significant, and all students of Japanese behaved like Brazilian Portuguese monolinguals, irrespective of whether they had been exposed to Japanese in late childhood or not.
This conclusion should be mitigated by two considerations. First, it is unlikely that sociolinguistic forces per se are the direct cause of the present pattern of results. It is more likely that sociolinguistic forces induce a change in amount of language usage, and that it is the amount of language use which causes changes in phonological representations. Second, as we suggested, sociolinguistic factors may well play a significant role during childhood, but not in adults who are acquiring a new language from scratch. In other words, age of acquisition remains a very important factor.