In this contribution, Rocco Pititto presents a reflection on the linguistics of Gustave Guillaume as natural starting point Ferdinand de Saussure, the father of general linguistics. His comment emphasizes the importance of the theoretical approach of Gustave Guillaume that was too often sidelined and almost ignored by the major currents of the twentieth century linguistics. He shows the commitment of Gustave Guillaume to studies that take into account both diachronic and synchronic aspects.