Languages vary as to the freedom with which they coordinate WH-expressions in coordinated-WH questions (CWHs) like When and where is the party?, which differ from familiar multiple-WH questions in the that they contain the conjunction and between two WH-expressions and require a multiclausal analysis (although monoclausal analyses have been suggested (Kazenin 2000, Liptak 2011)). On one end of the spectrum, English-like languages are very limited in their CWHs, while on the other end, Polish and its relatives allow free WH-coordination in CWHs. There seems to be little consensus in the literature as to what the underlying structure of these constructions is, with the two most prominent analyses being ellipsis (Giannakidou & Merchant 1998, Tomaszewicz 2010) and multidominance (Gracanin-Yuksek 2007, 2009).
In this talk, I present ongoing work on what licenses CWHs and whether multidominance and ellipsis can account for these properties. In particular, I focus on the observation -- based on comparing Polish, English, and Italian CWHs -- that the availability of pro-drop and/or optional transitivity seems to correlate with the degree of freedom to which languages allow CWHs with argument WH-expressions: If an argument can be somehow null in the main clause (as pro or as the missing argument of an optionally transitive verb), it can appear as a WH-phrase in a CWH. Independent analyses of seeming pro-drop in Italian (Cardinaletti 1994, Brandi & Cordin 1989) and Slavic (Gribanova 2013) allow us to more precisely compare the two main approaches to CWH. I demonstrate that the English, Italian, and Polish facts introduce further challenges to multidominance (ex. violations of the Constraint on Sharing (Gracanin-Yuksek 2013) by pro and problems with WH extraction) and ellipsis (issues of parallelism and coindexation).