The Swiss linguist Ferdinand de Saussure drew the distinction between langue ("language") and parole ("speech") during his classes in general linguistics. His students gathered their notes in the posthumously published Course in General Linguistics (1915).
According to Saussure, langue is "the work of a collective intelligence" and is the general sign systems of any language. It is a social convention that individuals cannot alter or change because it includes the general syntactic, phonetic and morphological rules according to which a given language works. Langue represents the potential aspect of language that individuals then put into practice with their acts of parole. Contrary to langue, parole has a more personal dimension as it identifies individual speech acts and a speaker's combinations of signs to form communication. Linguists and semioticians like Greimas and Jakobson have reinterpreted Saussure's distinction respectively as "system"/"process" and "code"/"message". Chomsky talks instead about "competence" and "performance". All these theorists have started their investigations on sign systems following de Saussure's assumption that every single process occurs according to a governing system of laws.