In syntax, sluicing is a type of ellipsis that occurs in both direct and indirect interrogative clauses. The ellipsis is introduced by a wh-expression, whereby in most cases, everything except the wh-expression is elided from the clause. Sluicing has been studied in detail in recent years and is therefore a relatively well understood type of ellipsis. Sluicing occurs in many languages.
Sluicing is illustrated with the following examples. In each case, an embedded question is understood though only a question word or phrase is pronounced. (The intended interpretations of the question-denoting elliptical clause are given in parentheses; parts of these are anaphoric to the boldface material in the antecedent.)
- Phoebe ate something, but she doesn't know what. (=what she ate)
- Jon doesn't like the lentils, but he doesn't know why. (=why he doesn't like the lentils)
- Someone has eaten the soup. Unfortunately, I don't know who. (=who has eaten the soup)
Sluicing in these examples occurs in indirect questions. It is also frequent in direct questions across speakers, e.g.
- Somebody is coming for dinner tonight. - Who? (=Who is coming for dinner tonight)?
- They put something in the mailbox. - What? (=What did they put in the mailbox)?
The examples of sluicing above have the sluiced material following its antecedent. This material can also precede its antecedent, e.g.
- Although I don't know why, the pictures have been moved. (=why the pictures have been moved)
- When and how is unclear, but somebody should say something. (=when and how somebody should say something)
Case-marking in sluicing
Interrogative phrases in languages with morphological case-marking show the case appropriate to the understood verb (as Ross 1969 and Merchant 2001 document), illustrated here with the German verb "schmeicheln" (to flatter), which governs the dative case on its object.
- Er hat jemandem geschmeichelt, aber ich weiß nicht, wem.
- he has someone.DAT flattered but I know not who.DAT
- "He flattered someone, but I don't know who."
Preposition-stranding in sluicing
Languages that forbid preposition-stranding in question formation also forbid it in sluicing (Merchant 2001), as in the following example from German:
- Er hat mit jemandem gesprochen, aber ich weiß nicht, *(mit) wem.
- he has with someone spoken but I know not with who
- "He spoke with someone, but I don't know (with) who."
In some languages, sluicing can leave behind more than one wh-phrase (multiple remnant sluicing):
- Someone wants to eat something. ?I wish I knew who what. (=who wants to eat what)
- ?Something is causing someone big problems, although it's not clear what who. (=what is causing who big problems)
Sentences like these are considered acceptable in languages like German, Japanese, Turkish, Russian, and others, although in English, their acceptability seems marginal (but see Bolinger 1978, Merchant 2001, and Richards 2010 for examples). Lasnik 2014 discusses the fact that the wh-phrase remnants in multiple sluicing must be clausemates:
- *Someone told me that something broke, but I don't remember who what. (≠who told me that what broke)
Islands in sluicing
Sluicing has garnered considerable attention because it appears, as Ross 1969 first discussed, to allow wh-fronting to violate the island conditions he discovered:
- They want to hire someone who speaks a Balkan language, but I don't remember which one. (=*which one they want to hire someone who speaks)
Ross (1969) is the first examination of sluicing; he argued that sluicing involves regular wh-fronting followed by deletion of the sister constituent of the wh-phrase. This analysis has been expanded in greater detail in Merchant (2001), the most comprehensive treatise on sluicing to date. Such analyses account directly for the case and preposition-stranding facts, but have difficulty accounting for the absence of island effects. A second kind of analysis is represented by Ginzburg and Sag (2000) and Culicover and Jackendoff (2005), both of which present nonstructural analyses of ellipsis, and do not posit unpronounced elliptical material. Such analyses must be supplemented in some way to account for the case facts; nonstructural analyses have not been shown to be able to handle the cross-linguistic distribution of preposition-stranding under sluicing, which appears to track preposition-stranding possibilities in non-elliptical questions. Yet another account of sluicing builds on the catena unit; the elided material is a catena.
Only the catena-based approach handles multiple sluicing without further elaboration. The structural movement analysis must rely on some other type of movement to evacuate the noninitial wh-phrase from the ellipsis site; proposals for this additional movement include extraposition or shifting. The nonstructural analysis must add phrase-structure rules to allow an interrogative clause to consist of multiple wh-phrases. The catena-based approach, however, does not account for the locality facts; since catenae can span multiple clauses, the fact that multiply-sluiced wh-phrases must be clausemates is a mystery.
- See for instance Ross (1969), Chung et al. (1995), and Merchant (2001).
- See Merchant's (2001) extensive account of sluicing; it includes examples from numerous languages.
- Concerning the catena unit as a basis for accounts of sluicing and of ellipsis in general, see Osborne et al. (2012) and Osborne (to appear).
- See Merchant (2001) for an account in terms of scrambling and Lasnik (2014) for an account in terms of shifting.
- Bolinger, Dwight. 1978. Asking more than one thing at a time. In Henry Hiz (ed.), Questions, 107-150. Reidel: Dordrecht.
- Chung, Sandra, William Ladusaw, and James McCloskey. 1995. Sluicing and Logical Form. Natural Language Semantics 3, 239-282.
- Culicover, Peter and Ray Jackendoff. 2005. Simpler Syntax. Oxford University Press: Oxford.
- Ginzburg, Jonathan and Ivan Sag. 2000. Interrogative Investigations. CSLI Publications: Stanford, Calif.
- Lasnik, Howard. 2014. Multiple sluicing in English? Syntax 17, 1, 1-20.
- Merchant, Jason. 2001. The syntax of silence: Sluicing, identity, and the theory of ellipsis. Oxford University Press: Oxford.
- Osborne, Timothy, Michael Putnam, and Thomas Groß 2013. Catenae: Introducing a novel unit of syntactic analysis. Syntax 15, 4, 354-396.
- Osborne, Timothy (to appear). Dependency grammar. In The Oxford Handbook of Ellipsis. Oxford University Press.
- Richards, Norvin. 2010. Uttering trees. MIT Press: Cambridge, Mass.
- Ross, John R. 1969. Guess who? in CLS 5: Papers from the fifth regional meeting of the Chicago Linguistic Society, eds. Robert Binnick, Alice Davison, Georgia Green, and Jerry Morgan, 252–286. Chicago, Illinois: Chicago Linguistic Society.