GALEN RECOGNIZED, As had Aristotle, three general types of sounds made by living creatures. Reflecting the Stoic influence, his categories were more selective than were his predecessors', however, as he did not consider nonvocal sound. His three divisions were voice, articulation, and human speech. 1 Voice, the basis of the other two, was effected by the larynx, the muscles which moved it, and the nerves which brought this motive power to the larynx from the brain. 2 Articulation was produced by the action of the tongue, nose, lips, and teeth. 3 Human speech possessed no distinctive instruments, but was created from voice and articulation, and differed from all other noises in that it was the method by which people conversed with each other.
This distinction is clearly manifest in the Greek text. When Galen discusses human speech, he refers to the aude or to the logos of the patient. When he is discussing the voice or the operation of the vocal instruments, he uses the word phone, and the term articulation is either arthra or dialektos. 4 Thus, in writing of his experiments conducted only upon animals or of his animal dissections, he never uses the words logos or aude.
Galen's investigations of the vocal instruments are in the seventh book of the treatise On the Use of Parts and the sixth book of the treatise On the Sites of Disease. The teleological orientation of the former is obvious, as it was designed not as an exposition of the mechanics of phonation, but as a demonstration of the dual purpose of the instruments of respiration. Therefore, in this text Galen was more concerned with refuting the doctrines of Erasistratus