Tim Hunter

Conservativity and Learnability of Determiners

A striking cross-linguistic generalisation about the semantics of determiners is that they never express non-conservative relations. To account for this one might hypothesise that the mechanisms underlying human language acquisition are unsuited to non-conservative determiner meanings. We present experimental evidence that 4- and 5-year-olds fail to learn a novel non-conservative determiner but succeed in learning a comparable conservative determiner, consistent with the learnability hypothesis.

Eliminating Rightward Movement: Extraposition as Flexible Linearization of Adjuncts

We propose an account of adjunct extraposition that does not invoke rightward movement. Instead, the noncanonical placement of adjuncts at the right edge of a sentence arises from the very same mechanisms that allow adjuncts to behave flexibly with respect to basic constituency tests and to avoid reconstruction. The system we propose naturally explains the locality restrictions on extraposition and certain interactions between extraposition and movement, and dovetails with an analysis of how adjuncts semantically compose with their hosts.

Exploiting syntactic relationships in a phrase-based decoder: an exploration

Phrase-based decoding is conceptually simple and straightforward to implement, at the cost of drastically oversimplified reordering models. Syntactically aware models make it possible to capture linguistically relevant relationships in order to improve word order, but they can be more complex to implement and optimise. In this paper, we explore a new middle ground between phrase-based and syntactically informed statistical MT, in the form of a model that supplements conventional, non-hierarchical phrase-based techniques with linguistically informed reordering based on syntactic dependency trees. The key idea is to exploit linguistically-informed hierchical structures only for those dependencies that cannot be captured within a single flat phrase. For very local dependencies we leverage the success of conventional phrase-based approaches, which provide a sequence of target-language words appropriately ordered and ready-made with any agreement morphology. Working with dependency trees rather than constituency trees allows us to take advantage of the flexibility of phrase-based systems to treat non-constituent fragments as phrases. We do impose a requirement—that the fragment be a novel sort of “dependency constituent”—on what can be translated as a phrase, but this is much weaker than the requirement that phrases be traditional linguistic constituents, which has often proven too restrictive in MT systems.

Deriving syntactic properties of arguments and adjuncts from neo-Davidsonian semantics

This paper aims to show that certain syntactic differences between arguments and adjuncts can be thought of as a transparent reflection of differences between their contributions to neo-Davidsonian logical forms. Specifically, the crucial underlying distinction will be that between modifying an event variable directly, and modifying an event variable indirectly via a thematic relation. I note a convergence between the semantic composition of neo-Davidsonian logical forms and existing descriptions of the syntactic properties of adjunction, and then propose a novel integration of syntactic mechanisms with explicit neo-Davidsonian semantics which sheds light on the nature of the distinction between arguments and adjuncts.

A Restriction on Vehicle Change and Its Interaction with Movement

This squib presents a restriction on the phenomenon descriptively known as ‘‘vehicle change’’ that has not, to our knowledge, previously been noted. With vehicle change construed as a kind of ‘‘tolerable mismatch’’ between an ellipsis site and its antecedent, the data we present suggest that exactly the same mismatches cannot be tolerated between the members of a movement chain. While in principle one might consider the possibility that ellipsis and movement could be reduced to the same operation (Chomsky 1995:252–253)—that the deletion usually described as ellipsis might be the same operation as the deletion or ‘‘chopping’’ (in the sense of Ross 1967) that applies to the unpronounced (usually lower) copy in a movement chain—the differences in the kinds of mismatches that can be tolerated will pose a difficulty for this unification. We present the crucial data that suggest that such a unification is not tenable in section 1 and then outline an explanation of these facts in section 2. We state this explanation in terms of the way movement, ellipsis, and vehicle change interact, while remaining largely agnostic about the exact mechanisms that implement these somewhat pretheoretic notions. In section 3, we consider the consequences for these more fine-grained questions about the nature of ellipsis and movement, and in section 4, we consider some further implications that depend on how vehicle change is understood. Section 5 addresses a challenge for our proposed explanation that turns out to be only illusory, and section 6 briefly concludes.