The maintenance of language minority children’s first language is often a desired outcome, but previous research has illustrated the difficulties of maintaining this language and shown that these children are susceptible to incomplete L1 acquisition. Visiting enrollment in the target language country has therefore received attention as a way to boost language minority children’s L1. This study aims to examine the effectiveness of such experiences on the Japanese ability of children of Japanese immigrants to the U.S. (whether their parents are married to Japanese or native English speakers). Four second-generation Japanese-English bilingual children (three of the children have American fathers and Japanese mothers, and one child has Japanese parents), aged 3;9 to 9;4, who were simultaneously acquiring English and Japanese as their first languages traveled with their parents to Japan on summer vacation and were enrolled in Japanese schools for four to six weeks. To examine the effects of their visiting enrollment, tape-recorded family conversations in natural settings were examined before their departure for Japan, twice during their stay in Japan, and twice after their return to the United States. Since postpositional particles are crucial elements for measuring the completeness of Japanese language acquisition, postpositional particle production by the children and their parents and errors made by the children during these conversations were examined. The major findings included the following: 1) Visiting enrollment furthered the Japanese acquisition of the children whose L1 Japanese was strong before their departure; 2) the children who did not show improvement in postpositional particle production made the kinds of errors that occur during L1 acquistion, others that occur during L1 attrition, and some that can be found in both L1 acquistion and L1 attrition. These findings give some insight into the effectiveness of visiting enrollment as a way to support the L1 of language minority children and also shed light on research on integrating L1 and L2 acquisition, L1 attrition, and incomplete L1 acquisition.
