Taking as its starting point significant similarities between a formal language model—Grammar Systems—and a grammatical theory—Autolexical Syntax—in this paper we suggest the application of the former to the topic of the latter. To show the applicability of Grammar Systems Theory to grammatical description, we introduce a formal-language-theoretic framework for the architecture of natural language grammar: Linguistic Grammar Systems. We prove the adequacy of this model by highlighting its features (modularity, parallelism, interaction) and by showing the similarity between this framework and (...) accepted and well-known grammatical models (e.g. Autolexical Syntax). (shrink)