This chapter studies the norms from a merely formal viewpoint, in order to concentrate exclusively on its logical-linguistic structure. The problem of legal norms making reference to theories of language and its different functions is a course of study which is used more in Italy. The chapter focuses on language in general, though spoken and written language as the most prominent form. From the formal-linguistic perspective, the legal norm is a proposition, which is to say it is a sequence of words endowed with significance. This differs from statements, as a lexical-syntactic group of linguistic signs with which a proposition is expressed. From the point of view or prism of the functions of language, it can be said that the norm is a or preceptive proposition. The chapter discusses on the various possible types of propositions, paying special attention to the so-called prescriptive or preceptive propositions.Keywords: legal norm; logical-linguistic structure; prescriptive proposition