This paper considers a Whorfian view of the relationship between language and thought in bilinguals, relating it to the speech production model of Levelt and colleagues and to the social contexts in which language use occurs. Bilingualism may produce general cognitive effects (e.g., enhanced skills in selective attention) and language-specific cognitive effects (e.g., differences in spatial descriptions as a function of language). Evaluation of experimental data provides no support for the general cognitive effects considered. In contrast, language-specific cognitive effects are demonstrable cross-linguistically but there is a lack of research on such effects within bilinguals. The paper closes with some suggestions for research.