The problems of access -- retrieving linguistic structure from some mental grammar -- and disambiguation -- choosing among these structures to correctly parse ambiguous linguistic input -- are fundamental to language understanding. The literature abounds with psychological results on lexical access, the access of idioms, syntactic rule access, parsing preferences, syntactic disambiguation, and the processing of garden-path sentences. Unfortunately, it has been difficult to combine models which account for these results to build a general, uniform model of access and disambiguation at the lexical, idiomatic, and syntactic levels. For example psycholinguistic theories of lexical access and idiom access and parsing theories of syntactic rule access have almost no commonality in methodology or coverage of psycholinguistic data. This paper presents a single probabilistic algorithm which models both the access and disambiguation of linguistic knowledge. The algorithm is based on a parallel parser which ranks constructions for access, and interpretations for disambiguation, by their conditional probability. Low-ranked constructions and interpretations are pruned through beam-search; this pruning accounts, among other things, for the garden-path effect. I show that this motivated probabilistic treatment accounts for a wide variety of psycholinguistic results, arguing for a more uniform representation of linguistic knowledge and for the use of probabilisticallyenriched grammars and interpreters as models of human knowledge of and processing of language.

This paper describes an efficient and robust implementation of a bidirectional, head-driven parser for constraint-based grammars. This parser is developed for the OVIS system: a Dutch spoken dialogue system in which information about public transport can be obtained by telephone. After a Review

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We discuss a generalization of Earley's algorithm to grammars licensing discontinuous constituents of the kind proposed by the so-called linearization approaches in Head-Driven Phrase Structure Grammar. We show that one can replace the standard indexing on the string position by bitmasks that act as constraints over possible coverage bitvectors. This improves efficiency of edge access and reduces the number of edges by constraining prediction to those grammar rules which are compatible with known linearization properties. The resulting parsing algorithm does not have to process the right-hand side categories in the order in which they cover the string, and so one can obtain a head-driven strategy simply by reordering the right-hand side categories of the rules. The resulting strategy generalizes head-driven parsing in that it also permits the ordering of non-head categories.

This paper describes a new, psychologically-plausible model of human sentence interpretation, based on a new model of linguistic structure, Construction Grammar. This on-line, parallel, probabilistic interpreter accounts for a wide variety of psycholinguistic results on lexical access, idiom processing, parsing preferences, and studies of gap-filling and other valence ambiguities, including various frequency effects. We show that many of these results derive from the fundamental assumptions of Construction Grammar that lexical idioms, idioms, and syntactic structures are uniformly represented as grammatical constructions, and argue for the use of probabilistically-enriched grammars and interpreters as models of human knowledge of and processing of language. Submitted to Cognitive Science ii 1 Introduction In the last twenty years, the field of cognitive science has seen an explosion in the number of computational models of cognitive processing. This is particularly true in the mode...

Head-Corner (HC) parsing has come up in computational linguistics a few years ago, motivated by linguistic arguments. This idea is a heuristic, rather than a fail-safe principle, hence it is relevant indeed to consider the worst-case behaviour of the HC parser. We define a novel predictive head-corner chart parser of cubic time complexity. We start with a left-corner (LC) chart parser, which is easier to understand. Subsequently, the LC chart parser is generalized to an HC chart parser. It is briefly sketched how the parser can be enhanced with feature structures. 1. Introduction "Our Latin teachers were apparently right", Martin Kay (1989) remarks. "You should start [parsing] with the main verb. This will tell you what kinds of subjects and objects to look for and what cases they will be in. When you come to look for these, you should also start by trying to find the main word, because this will tell you most about what else to look for". Head-driven or head-corner parsing has been ...

Object) TEACH Event: officer child animate living human other-animal adult plant horse (a) Lexicalized Conceptual Knowledge (b) Non-Lexical Concept Hierarchies (or Graphs) physicalobject abstractobject telescope opticalinsrument course thing lifeless object Figure 8.6: Representation of Conceptual Knowledge. 135 Though conceptual units state selectional preferences for role fillers, there is no completeness requirement that they must specify every role that can ever be attached to a concept. Optional roles such as a location role can be attached to any event, for instance. Once again, a distinction is made between required units and optional units and the representations are designed to distinguish between the two. The required roles, such as the agent, theme, and experiencer roles of a particular event for example, form the collection of roles that are typically present for the event. However, this is not a strict requirement constraint as in syntax. Some of the roles mentioned i...

We propose a relaxation of context-free grammar rules to handle languages with weaker linear precedence constraints. This proposal will serve as the basis of the design and implementation of a specialised computational formalism for parsing with linearisation domains in these languages. Some issues pertaining to the o-line compilation of speci cations are also discussed.

There is one and only one complete analysis of the sentence. (my translation) Die Sprache verkleidet den Gedanken. Und zwar so, daß man nach der äußeren Form des Kleides, nicht auf die Form des bekleideten Gedankens schließen kann; weil die äußere Form des Kleides nach ganz anderen Zwecken gebildet ist als danach, die Form des Körpers erkennen zu lassen. Die stillschweigenden Abmachungen zum Verständnis der Umgangssprache sind enorm kompliziert. — Wittgenstein (TLP 4.002) Language veils thought. And in such a manner that by the form of the cloak one cannot