Green makes the critical observation that models of lexical and semantic representation in bilingual memory fail to specify a mechanism that would enable the bilingual speaker to act. Under the conditions typical of most experimental research, bilinguals are asked to perform a well-defined task, such as word or picture naming, lexical decision, or translation. The question Green raises is how is it that the bilingual effectively performs one of these tasks rather than another? And within a given task such as word translation, how does the individual manage to produce words in one language and suppress the other? The goal of Green's proposal is to provide a preliminary account of the control apparatus that a bilingual would need to possess in order to perform effectively in this environment. An adequate model of these control mechanisms will presumably allow us to understand not only how bilinguals perform simple laboratory tasks, but also how they manage to engage the appropriate language during normal discourse, including code-switching with other bilingual speakers.