The purpose of this volume is to dispel some potential misconceptions about thestatus of Applied Cognitive Construction Grammar with regard to SLA and SLAresearch. This is important because, as we will see, most of the applied cognitiveapproaches on offer seek to align the insights of cognitive research with the essentialist SLA paradigm. SLA essentialism is the idea that observable or elicited performance reveals facts about non-observable mental representations. These facts are taken to be laws of sorts about the linguistic module and how L2 learners almost always fail to achieve a native-like proficiency. In point of fact, SLA has been criticized for propounding a view of L2 acquisition as a process of defective appropriation of the linguistic code among late learners. In this sense, SLA insiders like Ortega (2018) see in (psychological) essentialism the sole way toward the postulation of some truths about language learning and processing. As Ortega concedes, SLA researchers have been reluctant to ask questions about the nature of language or to provide a model of mind that supports their assertions about speakers' L2 use. In contrast to this reductionist view, I intend to show that applied cognitive approaches to language instruction do need to have a solid theoretical background that goes beyond performance to explain linguistic usage.