The parametrization of declarative feature

Abstract Numerous Southern Italian dialects are characterized by a dual complementizer system, with two declarative complementizers surfacing according to the class of the main verb, the mood of the embedded verb, the presence of left-peripheral elements, etc. This phenomenon is here investigated under the lens of the Parametric Comparison Method, an innovative tool for language comparison based on syntactic parameters. We argue that the occurrence of a dual complementizer in SIDs can be parametrized considering at least four parameters that regularize the operations of Grammaticalization, Checking, Strength and Spread . Therefore, an alternative view of the dual complementizer system is offered, suggesting that different structural operations play a crucial role in shaping the realized complementizer. This approach allows for a more nuanced understanding of the parametric differences and similarities among varieties that are traditionally grouped within the same linguistic area.