In this paper we consider the grammaticalization of subject agreement adducing
first–hand synchronic evidence from presentational VS constructions in Italo–Romance dialects. While the existing literature has placed emphasis on the pragmatic properties of the controller, we explore its semantic properties. We argue that variation in subject agreement can only be fully captured with reference to an independently established semantic scale of subjecthood that is based on the position of arguments in semantic representation, and hence on their lexical entailments (Jackendoff 1976; Dowty 1991; Van Valin and LaPolla 1997). Unaffected actor is the default controller in accusative alignment. The patterns of dialect microvariation arise, in our analysis, from parametric variation in macrorole assignment in presentational focus. Our proposal formalizes at the discourse–semantics–syntax interface the idea that, in presentational VS constructions, the core argument S may be treated as part of the predicate, thus failing to control grammatical subject agreement (Fuchs 1980). This happens in presentational focus because the predication is about an implicit topic (Benincà 1988, among others). The latter can trigger a type of pronominal agreement that is comparable to Bresnan and Mchombo’s (1987) anaphoric agreement. This study provides robust arguments in support of an understanding of subject agreement as the grammaticalization of semantic–relation contrasts, as well as pragmatic–role distinctions.