In a significant Latin chronicle, written by the Italian Franciscan Salimbene de Adam (born 1221-died after 1287/1288), one can examine how a scholar considered the vernacular languages. This paper focuses on the linguistic consciousness of the author, who is able to use linguistic and stylistic levels fitting the events related. The meaning of the words uulgaris and latinus is analysed in this text which makes use of many vulgar words latinized by appropriate endings and occasionally quotes sentences in French or in Italian dialect. While conscious of the evolution of Latin in the use of words, Salimbene feels a continuity from Latin to vernacular and seems to pay particular attention to morphological evolution.Besson Gisèle. In Vulgari su...