This paper focuses on some relationships between logic and natural languages, a topic that is crucial in Western philosophy (From Aristotle, to medieval Modistae, to Leibniz and the founders of modern mathematical logic). Specifically, the search for a universal grammar is considered in connection with linguistic typology (see Greenberg 's Universals of Grammar) and formalisms for knowledge representation. A preliminary investigation proves that usual linguistic concepts could be incorporated into a formal theory of general explicative power. This suggests a logical theory of grammars, where classical linguistic analysis is generalized and formalized. The conceptual and terminological apparatus of traditional grammars has two serious limitations: Greek-Latin dependence and informal (semantic and pragmatic) aspects.