Relative clauses in the diachrony of Italian

This paper investigates relative clauses (RCs) in the diachrony of Italian aiming at shedding light on the syntactic derivation of RCs. Building on Sauerland’s (2003) claim that RCs involve two non-distinct heads, Cinque (2008, 2013) unifies all RCs under a single derivation proposing that the two heads can either be both lexical or both null elements in syntax. When the two heads are lexical expressions, the RC will be lexically-headed, whereas when the heads are null elements, the RC will be headless, and thus a free RC. According to Cinque (2013: ch. 17), languages differ as to which head or which portion of heads they spell out according to the PF requirements available in a language. In some languages the internal head is always deleted at PF, in others it is spelled out, in some others both heads are fully spelled out, whereas in others languages portions of the heads can be spelled out. In this paper we argue that this variation may not be due to PF requirements only, but it depends on the syntactic derivation. We claim that the usual typology of RCs has to be enriched to include another type in which the two heads enter the derivation as distinct elements. The testing ground for our proposal is provided by the history of Italian. We show that, whereas in Modern Italian the two heads must be non-distinct, Old Italian allowed a configuration where the two heads differed, in the sense that the RC-external head could be a lexical expression while the RC-internal head a null element analogue to a free relative. We argue that the variation between Old and Modern Italian depends on the version of the matching relation involved in the Agree relation between the two heads. Whereas in Modern Italian the matching relation is set on its strict version, and thus results in identity between the two heads, in Old Italian matching involved an inclusion relation, thereby allowing the two heads not to be completely identical.