Revisiting Syntactic Microvariation and Diachrony in the Dual Complementizer Systems of Upper Southern Italy1

The primary aim of this work is to propose a diachrony of complementizer systems in the upper southern Italian dialects (USIDs). While previous diachronic studies have focused mainly on the transition from Latin to Romance, we aim to address several unanswered questions about the transition from medieval southern Italo‐Romance—in particular the system documented by Ledgeway (2005)—to the attested modern USID ones that are claimed to derive from it. Using the cartographic framework, and in particular the split‐CP (Rizzi 1997), our revisitation of the literature leads us to identify at least six distinct modern systems, which differ morpholexically (what we consider “dual” systems, e.g., presenting both che and ca) and/or syntactically (which we consider “split” systems, i.e., lexicalizing both Force° and Fin°). We ultimately propose that these systems should be interpreted as distinct stages in two separate diachronic developments. This is accounted for both through novel empirical insights concerning the conservative nature of the complementizer system found in e.g. Verbicarese—which we argue coincides with the one found in 17th–19th century Neapolitan‐‐, and through the view that complementizers are generated in Fin°, which presents theoretical advantages concerning the expression of (illocutionary) force and (modal)/finiteness marking.