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This thesis presents accounts of a range of linguistic phenomena in an extended categorial framework, and develops proposals for processing grammars set within this framework. Linguistic phenomena whose treatment we address include word order, grammatical relations and obliqueness, extraction and island constraints, and binding. The work is set within a flexible categorial framework which is a version of the Lambek calculus (Lambek, 1958) extended by the inclusion of additional type-forming operators whose logical behaviour allows for the characterization of some aspect of linguistic phenomena. We begin with the treatment of extraction phenomena and island constraints. An account is developed in which there are many interrelated notions of boundary, and where the sensitivity of any syntactic process to a particular class of boundaries can be addressed within the grammar. We next present a new categorial treatment of word order which factors apart the specification of the order of a h...

Many theories have been proposed to explain difficulty with center embedded constructions, most attributing the problem to some kind of limited capacity short-term memory. However, these theories have developed for the most part independently of more traditional memory research, which has focused on uncovering general principles such as chunking and interference. This article attempts to gain some unification with this research by suggesting that an interesting range of core sentence processing phenomena can be explained as interference effects in a sharply limited syntactic working memory. These include difficult and acceptable embeddings, as well as certain limitations on ambiguity resolution, length effects in garden path structures, and the requirement for locality in syntactic structure. The theory takes the form of an architecture for parsing which can index no more than two constituents under the same syntactic relation. A limitation of two or three items shows up in a variety o...

This paper presents a new approach to the recognition of sentence structure by computer in human languages that have variable word order. In a sense, the algorithm is not new; there is good evidence that it was known 700 years ago (Covington 1984). But it has not been implemented on computers, and the modern implementations that are most like it fail to realize its crucial advantage for dealing with variable word order. 1 In fact, present-day parsing technology is so tied to the fixed word order of English that researchers in Germany and Japan customarily build parsers for English rather than their own languages. The new

The central claim of this dissertation is that an elliptical VP is a proform. This claim has two primary consequences: first, the elliptical VP can have no internal syntactic structure. Second, the interpretation of VP ellipsis must be governed by the same general conditions governing other proforms, such as pronouns. The basic condition governing the interpretation of a proform is that it must be semantically identified with its antecedent. A computational model is described in which this identification is mediated by store and retrieve operations defined with respect to a discourse model. Because VP ellipsis is treated on a par with other proforms, the ambiguity arising from “sloppy identity ” becomes epiphenomenal, resulting from the fact that the store and retrieve operations are freely ordered. A primary argument for the proform theory of VP ellipsis concerns syntactic constraints on variables within the antecedent. I examine many different types of variables, including reflexives, reciprocals, negative polarity items, and wh-traces. In all these cases, syntactic constraints are not respected under ellipsis. This indicates that the relation governing VP ellipsis is semantic rather than syntactic. In further support of the proform theory, I show that there is a striking similarity in the antecedence possibilities for VP ellipsis and those for pronouns. Two

In this paper we examine three natural language uses of a recently developed logic grammar formalism- Assumption Grammars- particularly suitable for hypothetical reasoning. They are based on intuitionistic and linear implications scoped over the current continuation, which allows us to follow given branches of the computation under hypotheses that disappear when and if backtracking takes place. We also show two results which were surprising to us, namely: a) Assumption grammars allow a direct and efficient implementation of link grammars--- a context-free like formalism developed independently from logic grammars; and b) they offer the flexibility of switching between data-driven or goal-driven reasoning, at no overhead in terms of either syntax or implementation. 1 Introduction A grammar is a finite way of specifying a language which may consist of an infinite number of sentences. A logic grammar has rules that can be represented as Horn clauses. Logic grammars can be conveniently im...

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We propose an analysis of corrections which models some of the requirements corrections place on context. We then show that this analysis naturally extends to the interaction of corrections with pronominal anaphora on the one hand, and (in)definiteness on the other. The analysis builds on previous unification–based approaches to NL semantics and relies on Higher–Order Unification with Equivalences, a form of unification which takes into account not only syntactic βη-identity but also denotational equivalence. Wir schlagen eine Analyse vor, die einige der Anforderungen von Korrekturen an den Kontext modelliert und sich natürlich auf die Interaktion

This paper reports on an empirically based system that automatically resolves VP ellipsis in the 644 examples identified in the parsed Penn Treebank. The results reported here represent the first systematic corpus-based study of VP ellipsis resolution, and the performance of the system is comparable to the best existing systems for pronoun resolution. The methodology and utilities described can be applied to other discourse-processing problems, such as other forms of ellipsis and anaphora resolution. The system determines potential antecedents for ellipsis by applying syntactic constraints, and these antecedents are ranked by combining structural and discourse preference factors such as recency, clausal relations, and parallelism. The system is evaluated by comparing its output to the choices of human coders. The system achieves a success rate of 94.8%, where success is defined as sharing of a head between the system choice and the coder choice, while a baseline recency-based scheme achieves a success rate o,I:75.0 % by this measure. Other criteria for success are also examined. When success is defined as an exact, word-for-word match with the coder choice, the system performs with 76.0 % accuracy, and the baseline approach achieves only 14.6% accuracy. Analysis of the individual components of the system shows that each of the structural and discourse constraints used are strong predictors of the antecedent of VP ellipsis. 1.

We report the results from three cross-modal lexical decision experiments investigating antecedent priming effects in Japanese. In the first two experiments we examined antecedent reactivation at the preverbal trace position in long-distance scrambling sentences. We found an interaction between the participants' working memory (WM) span and antecedent priming. For the High Span Group, the magnitude of antecedent priming at the trace position was significantly larger than at the earlier control position; for the Low Span Group, on the other hand, there was no such difference. In a third experiment, we examined whether similar reactivation effects cotfid be observed for argument expressions that are not base-generated adjacent to the verb. Contrary to scrambled objects, subject NPs in canonically ordered sentences were not reactivated at the preverbal test position in either of the two participant groups. We argue that the priming effect observed in the High Span Group supports a trace-based account of long-distance scrambling. The degree of complexity of the experimental sentences was such, however, that they exceeded the memory span of the Low Span Group. We conclude that argument traces access their antecedents irrespective of the position of their subcategorizers.