Hello,
Ferdinand de Saussure is called the father of modern linguistics for one reason in particular.
We consider that he based the modern linguistics and established the bases of the semiology. In his Cours de linguistique générale in 1916, published after his death by his pupils, he defines certain fundamental concepts (distinction between language and word, between synchrony and diachrony, arbitrary character of the linguistic sign, etc.) which will inspire not only the later linguistics but also the other sectors of the human sciences as the ethnology, the literary analysis and the philosophy. It's for that reason De Saussure is regarded as the father of modern linguistics.
:)
