Despite intentions to raise children in two home languages, non-Japanese bilingual homes may be encouraging the development of the societal language in children born in Japan. This article investigates: (1) the language use of two trilingual mothers with their developing trilingual children, and (2) how the mothers respond to their children's use of the societal or majority language in the home environment. Both families considered their toddlers to be dominant in Japanese, although the children have been exposed simultaneously from birth to two other languages at home and did not hear Japanese until they entered community-based daycare centers at ages 0;5 and 0;11, respectively. Both mothers used similar discourse strategies that inadvertently encouraged their children between ages 1;1 and 2;1 to use Japanese in the home context. Although one child was a passive or receptive trilingual, the other became an active one, resulting in the conclusion that parental discourse strategies encouraging bilingual contexts are not absolutely detrimental to active multilingualism, not only because they are necessary for smooth interactions in the earliest stages of language acquisition, but also because they may help support more than one minority language in the home context. (Contains 4 figures and 4 tables.)