This is an ethnographic and discourse analytic case study of a bilingual, minority-language family of a six-year-old child with autism whose family members were committed to speaking English with him. Drawing on "family language policy," the study examines the tensions between the family members' stated beliefs, management efforts, and their actual practices around language use with their child. The findings show that many assumptions held by family members about language use and bilingualism were inconsistent with their everyday language practices. A practice and discourse-analytic approach to bilingualism offers a theoretical and methodological lens through which to investigate these discrepancies and to recast the interactional achievements between the child and his parents as situated bilingual practices.