This paper describes an opportunity for theoretical linguists to make a particular sort of contribution to the teaching of second-language (L2) grammar. Currently, a popular procedure in L2 instruction for teaching grammar is indirect Written Corrective Feedback (WCF). In this procedure, instructors do not provide corrections but rather merely flag L2 students’ errors with proofreading symbols. These symbols are intended to guide learners to self-correct errors, and it is hoped that through this process, learners might make fewer errors in future writing with these points of grammar. Despite its widespread use, there is evidence that indirect WCF only leads to increased competence for a limited subset of grammatical patterns, exerting no significant positive effect with points of grammar not in this subset. A plausible explanation in such cases is that indirect WCF can fail to provide learners with sufficient feedback to acquire the grammatical paradigm. In such cases, direct WCF may be more helpful, but there is another option, which is to supplement indirect or direct WCF with metalinguistic explanation (ME) of targeted grammatical structures. However, the exact nature of this ME could be critical. As the view of language acquisition depicted under Skill Acquisition Theory (SAT) would predict, learners would specifically require ME that consists of accurate and concisely formulated declarative knowledge of the grammar point in a format that permits the pattern to be proceduralized and eventually automatized. Since formulating concise, accurate, and proceduralizable declarative knowledge for grammar points is a challenge in and of itself, theoretical linguists could pursue this objective and thus helpfully make a particular contribution to L2 grammar instruction. Addressing learner errors involving the articles in English is discussed as an example.