Conclusions

Se, the complementizer introducing embedded yes/no questions in Italian, fills a position in the C system which is lower than Force, the position filled by the declarative complementizer che, but higher than Focus and the position filled by Wh elements in embedded questions. Perché  and other wh elements corresponding to higher adverbials can fill the position of Spec of INT (at least when construed locally); this explains why such elements can cooccur with a following focus in both main and embedded questions; it also helps us to understand why these elements do not trigger obligatory I to C movement in main questions.