From Need to Necessity

Abstract. We trace the evolution of the Italian verb bisogna from a lexical verb expressing need in Old Italian to a modal verb of necessity in Modern Italian (cf. Benincà & Poletto 1993, 1994, 1996). According to the standard view (Roberts 1985; Pollock 1989) loss of its theta-role content turns a lexical verb into an auxiliary. Our own view is that theta-roles are not lexical primitives but are construed at the interface on the basis of the formal features of a lexical item and the syntactic level which construal targets. We assume that the lexical content of bisogna has remained constant throughout history, and suggest that a morphosyntactic change in the grammar has resulted in the assignment of theta-roles to bisogna on a different level in the modern language than in the old language.