Ferdinand Mongin de Saussure was a Swiss linguist and semiotician. His ideas laid a foundation for many significant developments both in linguistics and semiology in the 20th century. He is widely considered one of the founders of 20th-century linguistics and one of two major founders of semiotics/semiology. One of his translators, Roy Harris, summarized Saussure's contribution to linguistics and the study of "the whole range of human sciences. It is particularly marked in linguistics, philosophy, psychology, sociology and anthropology." Although they have undergone extension and critique over time, the dimensions of organization introduced by Saussure continue to inform contemporary approaches to the phenomenon of language. Prague school linguist Jan Mukařovský writes that Saussure's "discovery of the internal structure of the linguistic sign differentiated the sign both from mere acoustic 'things'... and from mental processes", and that in this development "new roads were thereby opened not only for linguistics, but also, in the future, for the theory of literature". Ruqaiya Hasan argues that "the impact of Saussure’s theory of the linguistic sign has been such that modern linguists and their theories have since been positioned by reference to him: they are known as pre-Saussurean, Saussurean, anti-Saussurean, post-Saussurean, or non-Saussure".

https://en.wikipedia.org/wiki/Ferdinand_de_Saussure