Examined are the consequences of bilingualism on children's ability to formulate scientific hypotheses or solutions to science problems & interactions of this ability with aspects of linguistic competence. Experimental group treatment consisted of 12 science inquiry film sessions & 6 discussion sessions, all taught by the same teacher in English. The quality of scientific hypotheses and the complexity of the language used to express them were found to be significantly higher for both experimental groups than for the control groups. However, the bilingual children, given the same instruction by the same teacher in formulating scientific hypotheses, consistently outperformed monolingual children both in the quality of hypotheses generated and in the syntactic complexity of the written language. One implication is that a well-organized bilingual program where children develop in two linguistic perspectives can make the positive interactions of cognitive functioning & language development more fully operative.