A Typologically Unusual Interrogative Word in Toqabaqita and Other Oceanic Languages

In Toqabaqita and some other Oceanic languages the reflexes of Proto-Oceanic *sapa "what?, which?" are used to inquire about parts of whole and/or about kinship relations; for example, Toqabaqita tafa "which part of person's or animal's body?". While these interrogative functions may be unusual cross-linguistically outside of Oceanic, in Oceanic they follow naturally from a grammatical property of Proto-Oceanic, specifically the use of one type of attributive possessive construction to encode inalienable-possession relations.