The typical speech of (fluent) bilinguals in monolingual settings contains few switches into the non-target language. Apparently, bilinguals can control what language they output. This article discusses views on how bilinguals exert control over their two languages in monolingual tasks, where participants only have to implicate one of their languages in performing the task, and in translation and, especially, simultaneous interpreting, tasks that can only be performed if both languages are addressed. A distinction is made between "global" control, where control involves the activation and/or inhibition of complete language systems, and "local" control, where control impacts on a restricted set of memory representations. A number of studies suggest that bilingual control is a special case of the control of action in general. This insight suggests an opportunity to incorporate relevant work in the field of translation studies in the study of bilingual control, embedding it in the same theoretical framework.
de Groot, A. M. B., & Christoffels, I. K. (2006). Language control in bilinguals: Monolingual tasks and simultaneous interpreting. Bilingualism-Language and Cognition, 9(2), 189-201. https://doi.org/10.1017/S1366728906002537