An enthusiastic interest in the Italian language and its vocabulary marks Antonio Rosmini’s adolescence, as six autograph notebooks reveal. They show an early, but resolute and determined passion towards linguistic studies. To date, Rosmini’s notebooks have not been critically studied as yet. They contain more than 1500 notes, which reveals the seriousness and the commitment of Rosmini’s work. By summarizing the origin and the development of the project of a new edition of the Vocabolario della Crusca, the authors seek to frame a historical-linguistic analysis of a selected amount of notes (“postille”) which they consider to be the most meaningful ones for this purpose and which are taken from the first notebook, and which are thought to be the most considerable sets of notes among the six notebooks.