ABSTRACT : This paper outlines a reconstruction of the conceptual tradition according to which thought is an internal language. The early transformations of the traditional language of thought hypotheses are examined, from Plato's thesis that thought is a silent dialogue of the soul with itself to Porphyry's synthesis in which Plato's claim is grafted on the Stoic dichotomy of internal and preferred speech and on the Aristotelian trichotomy of written letters, spoken sounds and affections of the soul. This synthesis is the philosophical origin of the medieval très oraliones scheme, according to which there are three states of discourse : written, spoken and mental.RÉSUMÉ : Cet article a pour but d'esquisser une reconstruction de la traditio...