This document discusses Ferdinand de Saussure's concepts of langue vs parole and the sign. It explains that for Saussure, language (langue) is the system of rules and conventions of a speech community, while speech (parole) is the individual realization of language in actual communication. The document also summarizes Saussure's concept of the linguistic sign as being composed of both a signifier (expression) and signified (concept), and notes two important postulates of his theory: the arbitrariness of the sign and linguistic value.