The main aim of this article is to provide a detailed analysis of particular structures found in Italian, especially as spoken in central and southern Italy, and in Sicilian. These structures are very similar in the two languages, in that they involve the grammaticalization of the same verb of saying or epistemic adjective followed by the complementizer (cf. Italian dice che , capace che , and Sicilian dicica , capacica ), but in fact they display different properties. I investigate the function and the syntactic behaviour of these constructions, which seem to instantiate two types, stages or degrees of grammaticalization. More specifically, I show that in Italian these predicates are functional heads followed by the complementizer che , while in Sicilian the resulting units are now sentence adverbs. The present work therefore deals with grammaticalization and language change, but also with the two categories with which these structures are associated, namely, evidentiality and epistemic modality. A broader theoretical question lies in the background of the discussion, which challenges the ‘morphocentric’ perspective on the grammatical expression of certain categories such as evidentiality (cf. Aikhenvald 2004). Following Cinque (1999, 2004), I claim that adverbs can also be seen as the overt manifestation of functional distinctions, similarly to particles, auxiliaries and overt morphology. Under this view, sentential adverbs are functional in nature, and have the same meaning and function as the corresponding grammatical elements occurring as the head of the corresponding functional projection.