Acquired in the framework of the educational experiences of Celestino Fabriani, the priest educator of the deaf in the Eighteenth Modena, his Grammatics (1845, 1875) is a mature fruit of linguistic rationalism in Italy. Linked to the linguistic reflection submitted in the Logical Letters to Marcantonio Parenti (1838), the aim is to overcome the limits of the predominantly descriptive and prescriptive processes, which are considered unsuitable for differential teaching. Grammatics are made up of grammairiens philosophes and idéologues and, through them, of Portoreale and were printed in the second postuma and final edition, revised by a collaborator, in 1875. The interest of this text lies above all in the special attention paid by the author to ‘special’ teaching needs and their theoretical impact, to the extent to which they make rather innovative choices. In particular, the author proposes that the technical reference vocabulary be re-established on ethymological bases, so that it is connected in a transparent manner to recognised logical functions working in language; it is an acrybia to describe the functional characteristics of a large number of linguistic elements (this is particularly true in the chapters on referrals and situants: this is the name he gives to a number of prepositions and adversaries); is committed to streamlining the system of the parts of the speech. From a global educational point of view, on the other hand, the emphasis placed on F.’ s attention to the applicability of his model is considerable, so that the sounds of rationalist thinking here combine with the requirements of a hands-on exercise based on practice and sensitive to the needs of special users (and thus open to the reflections and experiments carried out in particular in France and Italy by De l’Épée and the Assarotti); his system is therefore a compromise system in which natural methods are combined with guidelines and grammatically oriented. Strictly speaking, however, the linguistic paradigm proposed by F. remains traditional: the authors cited in the Grammatics do not date back more than half of the 18th century and provide an exhaustive overview of the literary language, but does not show any evidence of openness to forms of live use, other than in the lexical sector (and therefore in a sector that is not directly responsible for it), even though they do not essentially show puristic inclinations. Moreover, this can be explained by the fact that the faith had been formed and operated in a politically and culturally conservative environment and that the rationalistic models on which it is based appear to be largely anchored, when they show interest in teaching, in classic frameworks that validate the quintilianeus archetype of consensus bonorum. An example of linguistic rationalism in Italy: Severino Fabriana’s grammar for the deaf and dumb (1845, 1875) Developed in the context of the educational experience of Celestino Fabriani, a Priest and educator for the deaf and dumb in Modena in the nineteenth century, his grammar (1845, 1875) is a product of linguistic rationalism in Italy. Linked to the linguistic reflections in Logical Letters by Marcantonio Parenti (1838), Fabriani aimed to overcome the limits of predominantly descriptive and prescriptive grammar that they were considered unsuitable for differentiated teaching. The grammar puts the model of Grammairiens philosophes and Idéologues to good use as well as that of the Lords of Port-Royal and the second and final edition was printed in 1875. The interest in this text lies in the power’s focus on the need for “special” education and the theoretical implications of this leading to innovative shocks. In particular, the author proposed to radically revise the technical Lexicon on an etymological basis, so that it was transparently linked to logical linguistic functions. HE described the functional characteristics of a large number of linguistic elements and made an attempt at rationalising the system of parts of speech. From a teaching point of view, Fabriani paid great attention to the applicability of his model, combating rationalism with a language teacher strategy that was sensitive to the needs of special users (and open to reflections and Experiments carried out in France and Italy by De l’Épée and Assarotti). It was a system in which natural, direct and grammatically oriented methods were combined. Strictly speaking, the linguistic paradigm proposed by Fabriani remains traditional: the authors quote do not date back beyond the second half of the [teenth century. HE offers an exhaustive landscape of literary language, showing no openness to common use, if not in the Lexis, without puristic inclinations. This can be explained by the fact that he had been translated and processed in a politically and culturally conservative environment and that the rational models which Inspired him was anchored to a classic framework which validated the Quintilian archetype of consensus bonorum.