In the European Middle Ages, what is generally called philosophy of language is represented by a philosophy of the word, not only the scholastic one of the word as ‘part of speech’, developed by the Modistae, but from the 4th century onward, a patristic doctrine of the human word as compared with the divine Logos. It is based on the idea of an original ‘word’, independent of language, which, as a part of inner knowledge, is a formed thought. What is usually called ‘word’ is only its rendering by the human voice: the outer word as opposed to the inner word. The rudiments of this doctrine are found in Irenaeus (2nd century), it is clearly formulated by Basileios the Great (330–379), but philosophically founded, developed, and defined in Augustine’s (354–430) “De Trinitate”. Here the dichotomy of the intellectual and the vocal word is expanded to a trichotomy, i. e., a triplicity of the word: first the ‘verbum cordis’, a mentally envisioned element of cognition, the real and proper word and causa efficiens of the other verbal manifestations, i. e., second: the realization of the mental concept in a human language, but only imagined, not voiced, the proper vehicle of human thinking; and third: the spoken word, which is the sensible transient sign of an intelligible permanent idea. The ‘verbum cordis’ is essential and self-sufficient; but as ideas are only communicable by means of material signs the second and third words are necessary contrivances. This Augustinian doctrine lived on for more than 800 years; during that period it was either repeated exactly or with a somewhat different terminology or rendered with slight notional modifications, first, in the 8th century, by John of Damascus, then in the 11th century by Anselm of Canterbury, and finally in the 13th century by Albertus Magnus, Bonaventura, and Thomas Aquinas. Of all those followers Thomas shows the profoundest and precisest conception of the ‘verbum cordis’, which remains the core of that impressive abstract construction: the triple word theory.