The dissertation consists of theoretical and experimental studies of multiple interrogatives (i.e., sentences containing more than one wh-phrase, like Who bought what?). First, I examine the status of Superiority effects in contexts with and without subject-aux(iliary) inversion cross-linguistically. The relevant contrast from English is between Who bought what?, ??What did who buy?, and I wonder what who bought., where () indicates a greater degree of unacceptability by native speakers than (??). I argue that the presence of subject-aux inversion in main clauses in English is responsible for the given asymmetry, and I attribute the degraded status of ??What did who buy? to the independent semantic properties of questions.

Next, I explore the semantic properties of multiple interrogatives in detail. I develop an analysis that does not rely on covert wh-movement, relying instead on the syntactic position of the Question morpheme. I also explore the nature of complex wh-phrases (e.g., what boy, which book). I propose that choice functions are part of complex wh-phrases but not bare wh-phrases.

I then explore the behavior of multiple interrogatives under Sluicing (i.e., clausal ellipsis). I observe that, in Slavic, it is possible to have multiple wh-phrases as well as focused referential expressions as remnants of sluicing. Based on this data, I argue that clausal ellipsis is licensed by focus in general. I also explore the apparent Superiority effects under sluicing in Russian and Polish and conclude that those are, in fact, parallelism effects, and not minimality effects.

Finally, I present the results of several language acquisition studies on at what age and how English-, Russian-, and Malayalam- speaking children acquire the language-specific syntactic and semantic properties of multiple interrogatives, given the limited evidence in the input. I report the results of the corpus studies of parental speech with respect to the frequency of occurrence of multiple interrogatives, as well as the results of the studies, where multiple interrogatives were elicited from children and adults in specific contexts. I conclude that young children acquire syntax and semantics of multiple interrogatives quite successfully. I then discuss what evidence in the input they might be using.