This study examines the relationship between caregivers' conversational styles in One-Person-One-Language (OPOL) settings and early bilingual development. In particular, it attempts to demonstrate that interrogative styles may have an impact on bilingual children's responsiveness in two language contexts. It is based on longitudinal data of a bilingual child from ages 1;3 to 2;3 interacting with his English-speaking mother and Japanese-speaking grandmother. Results from a functional analysis of caregiver questions based on McDonald and Pien's model revealed that, for a given period of time, the bilingual child was exposed to a more tutorial style of interrogation in English, which frequently used questions to examine his knowledge, and a more child-centered style of interrogation in Japanese, which sought information about his feelings and needs. The contrasting interrogative styles led to varying rates of responses and contributed to faster development in English than in Japanese. (Contains 4 figures and 2 tables.)