Word order optionality in question formation in Chinese copula clauses

Alongside superiority shi shenme ‘what is superiority?,’ which displays a canonical word order, the order shenme shi superiority is also possible in Chinese. In this paper I argue that this optionality results from a derivation that starts with merger of the two heads shenme ‘what’ and superiority, which generates a head-head structure that cannot be labeled under Chomsky’s labeling algorithm. The system must therefore resort to movement of either shenme or superiority in order for the structure to be labeled. Evidence for this analysis comes from the fact that when the sentence contains phrasal elements like shenme yisi ‘what meaning’ or shenme ren ‘what person,’ the optionality disappears. I also examine examples involving other interrogative items in the language and claim that this optionality only obtains with shenme ‘what’ and shei ‘who,’ other superficially similar word order patterns being different in terms of their semantic properties. Finally, I discuss the implications of this analysis in the context of symmetry-breaking in the sense of Moro (2000) and of Chomsky’s (2013) labeling algorithm.