The Stoics made linguistics an important part of their system of the cosmos and the human. They played an important role in defining the linguistic sign-terms adopted later on by Ferdinand de Saussure like "significant" and "signifié". The Stoics studied phonetics, grammar and etymology as separate levels of study. In phonetics and phonology the articulators were defined. The syllable became an important structure for the understanding of speech organization. One of the most important contributions of the Stoics in language study was the gradual definition of the terminology and theory echoed in modern linguistics.