In the field of educational psychology, self-regulation is part of a well-established research paradigm that has been extensively applied to learning contexts. However, despite proposals highlighting its benefits, some researchers claim that its cross-pollination into applied linguistics has been slow. In their recent "Applied Linguistics'" Forum article, Teng and Zhang (2022) discuss some of the reasons why this may be the case. They also further repeated calls for the importance of self-regulated learning in second/foreign language learning and teaching. In this response article, we wish to add to their proposal by focusing on the role that language plays in language learning. Specifically, to maximize the benefits of second/foreign language learning and teaching centered on regulatory training (whether it is self-, co-, or otherwise derived), then alongside the "how" (learning process), we need to more fully consider the "what" (aspect of language being learned), and how the two are, in essence, mutually constitutive and reciprocally conditioned. This entails broadening our perspective on self-regulated learning to encompass the multi-functional nature of language use.