A question of strength: on NPIs in interrogative clauses

We observe that the facts pertaining to the acceptability of negative polarity items (henceforth, NPIs) in interrogative environments are more complex than previously noted. Since Klima [Klima, E. (1964). In J. Fodor & J. Katz (Eds.), The structure of language. Prentice-Hall], it has been typically assumed that NPIs are grammatical in both matrix and embedded questions, however, on closer scrutiny it turns out that there are differences between root and embedded environments, and between question nucleus and wh-restrictor. While NPIs are always licensed in the nucleus of root questions, their acceptability in the restrictor of wh-phrases and in the nucleus of any embedded question depends on the logical properties of the linguistic environment: its strength in terms of exhaustivity [Groenendijk, J., & Stokhof, M. (1984). Studies on the semantics of questions and the pragmatic answers. Amserdam (NL), Post-Doctoral Dissertation. Heim, I. (1994). In R. Buchalla & A. Mittwoch (Eds.), Proceedings of the 9th annual IATL conference and of the 1993 IATL workshop on discourse (pp. 128-144). Akademon, Jerusalem. Beck, S., & Rullmann, H. (1999). Natural Language Semantics, 7, 249-298. Sharvit, Y. (2002). Natural Language Semantics, 10, 97-123] and its monotonicity properties (in the sense of von Fintel [von Fintel, K. (1999). Journal of Semantics, 16, 97-148]).