This article is concerned with an intricate interaction between syntax and semantics. The place of this interplay is Force and Focus. The model which guides our analysis is Rizzi 1997, 2004 and its split of the C-system into several categories. With regard to these concepts, we compare Italian and European Portuguese, in some structures we analyze Brazilian Portuguese variants. Our investigation sustains Longobardi’s 2001 Inertial Theory which claims that syntactic change – and we add variation – can only be caused by or correlated with changes at the interface, that is Logical Form or Phonetic Form. In our article we propose that the semantic change respective variation in some quantifiers results in syntactic differences or changes.