The status of complementizers in the left periphery

In section 1 we argue that the nominal nature of complementizers in many languages (notably wh- items in Romance) points to the conclusion that this extra embedding layer is nominal (cf. Rosenbaum 1967). In section 2 we address the question whether the structures they create are more similar to headed relatives (Arsenijevic 2009, Kayne 2010, to appear) or to free relatives (Manzini and Savoia 2003, 2005, 2011). In section 3 we consider some of the empirical reasons that would recommend distinguishing between complementizers and wh- items, including selection, islands and order in the left periphery. We also consider finiteness restrictions (section 4). In section 5 we conclude by indicating what this line of research implies for Main Clause Phenomena.