The autor analyzes in this article to what extent fifteenth century Florentine political thinkers –Matteo Palmieri in particular– considered that the subject of language and education contributed to teinforce civic feelings and convictions in the Italian communae. Palmieri’s attention was devoted to the communa of Florence, which at the said time was undergoing a crisis in its pattern of organization. Education contributed to model good citizens. Simultaneously popular language, in spite of much esthetical criticism and confrontations between localisms throughout the Peninsula, was trying to impose itself as a koiné which would be an agent of identification for a whole region and could contribute to propagate political and religious ideas and favor mutual understanding.