Bilinguals change their way of communicating when they are with monolinguals and when they are with bilinguals who share their languages. Whereas they avoid using their other language(s) with monolinguals (they are in a monolingual mode), they may call upon it (or them) when interacting with bilinguals, either by changing over completely to the other language(s) or by bringing elements of the other language(s) into the language they are speaking (they are then in a bilingual mode). The author reviews how he developed the notion of language mode, which, at the cognitive level, implies a change of activation of the languages and processing mechanisms. He summarizes some of the basic elements of language mode as described in a 2001 seminal chapter, discusses how language mode has fared since, and presents additional evidence for it. He then proposes some follow-up comments that deal with the level of activation of the deactivated language(s) in a monolingual mode, the complex nature of the variable that is language mode, and how it compares to the adaptive control hypothesis. He ends with reactions to language mode – many positive and some critical.