ABSTRACT Littlewood’s early stance on the use of students’ first language (L1) in the foreign language (L2) classroom was that maximum use of the target language (TL) enhances language acquisition. He suggested that this precept has been pervasive in every communicatively-oriented language teaching method and has also been widely accepted in official curricula in a range of contexts due to an understanding that TL use should be normative in classroom interactions. A strong rationale for advocating this ‘monolingual principle’ has been that, for many students, the L2 classroom provides the only opportunity to be exposed to the TL. Littlewood and Yu (2011. First language and target language in the foreign language classroom. Language Teaching 44, no. 1: 64–77) recognised, however, that teachers and students do make use of students’ L1 in L2 classrooms and suggested several ways in which teachers might do this legitimately. Furthermore, Littlewood (e.g. 2014. Communication-oriented language teaching: where are we now? Where do we go from here? Language Teaching 47, no. 3: 349–362) conceded that exclusive TL use has become subject to active questioning in recent years. The phenomenon of translanguaging takes arguments that support L1 use beyond Littlewood’s earlier suggestions. There are also implications for TBLT where extensive L2/TL use is the default position but where translanguaging practices are not necessarily at odds with the central task construct. This paper explores translanguaging in the contexts of TBLT and the monolingual principle.