The aim of the article is to present a usage-based theory of second language acquisition (SLA) which might serve as a framework for explaining the learning mechanisms that are operating when students are exposed to the meaningfully-motivated Cognitive Grammar-based teaching materials. Currently, two seemingly quite different stands of Cognitive Grammar (CG) applications are advocated: one focusing on the use of meaningfully-motivated linguistic explanations and the other on the usage-based nature of language. The article outlines a unified psycholinguistic theory, inspired by Brian MacWhinney"s Competition Model and developed by Nick C. Ellis, which is compatible with both the meaning-based and the usage-based conceptions of language assumed by CG, and which can provide a more fine-grained frame of reference for introducing Cognitive Grammar into the teaching practice. Finally, some suggestions are made concerning practical application of CG-inspired pedagogical rules that should enhance the effectiveness of meaningfully motivated grammatical instruction.
