ϕ-Agree and Person Feature Identity in Romance Auxiliary Selection

This dissertation deals with Romance auxiliary selection from a Minimalist perspective (Chomsky, 1993, 1995). The overall theory developed here is in- spired by the co-indexation approach (Burzio, 1986; Ledgeway, 2020, 2022) and the person feature identity approach (Olivier, 2025). These approaches share the common assumption that the auxiliary BE signals an identity re- lation in the T/v field. While this assumption centres the pattern found in languages such as Italian and French, commonly referred to as an argument- structure-based system of auxiliary selection, it does not readily account for other Romance patterns, such as person-driven and mixed systems. Thus, the aim of this work is two-fold. It provides an analysis of argument-structure- based systems, exemplified by Standard Italian, and explores the factors that make person-driven and mixed systems, found in many Central and Southern Italian dialects, unrelated (person-driven systems), or apparently unrelated (mixed systems), to the general assumption regarding BE selection presented above. The syntactic analysis exploits the Share mechanism, first proposed by D’Alessandro (2017). This mechanism has already been applied by Olivier (2025), in a partially different version, to French auxiliary selection. In this dissertation, I rely on Olivier’s interpretation of Share, with some differences. The Share mechanism is integrated in a Minimalist-based model where syntactic operations are feature-driven and insertion of morpho-phonological material takes place through rules of insertion at PF. The parametric differ- ence between the various systems of auxiliary selection is attributed to the featural properties of v. In argument-structure-based systems, v is able to enter in a Share relation with a higher vAux, associated with the auxiliary, in unaccusatives and reflexives. In person-driven systems, instead, vAux entertains a local Agree relation with the subject (D’Alessandro and Roberts, 2010; D’Alessandro, 2017; Amato, 2021, 2022). As for mixed systems, I argue that they can be grouped with argument-structure-based systems, provided that their specific pattern is accounted for by posing person restrictions on T, as proposed by Amato (2021, 2022). The syntactic analysis is extended to Old Florentine, an Old Italian variety with a partly different pattern from that of Modern Italian. To the best of my knowledge, the analysis proposed for this particular variety fills a gap in the Minimalist literature and opens the way to further investigations on the diachronic development of Italian auxiliary selection. The overall approach does not treat auxiliary selection and past participle agreement as entirely separate phenomena. As a matter of fact, the syntactic analysis provided in this dissertation suggests the variability related to systems of auxiliary selection is connected to the structural relation between the auxiliary and the participle, influenced by the specific structural properties of the participle.