Linear Logic for Meaning Assembly

Semantic theories of natural language associate meanings with utterances by providing meanings for lexical items and rules for determining the meaning of larger units given the meanings of their parts. Meanings are often assumed to combine via function application, which works well when constituent structure trees are used to guide semantic composition. However, we believe that the functional structure of Lexical-Functional Grammar is best used to provide the syntactic information necessary for constraining derivations of meaning in a cross-linguistically uniform format. It has been difficult, however, to reconcile this approach with the combination of meanings by function application. In contrast to compositional approaches, we present a deductive approach to assembling meanings, based on reasoning with constraints, which meshes well with the unordered nature of information in the functional structure. Our use of linear logic as a `glue' for assembling meanings allows for a coherent treatment of the LFG requirements of completeness and coherence as well as of modification and quantification.Comment: 19 pages, uses lingmacros.sty, fullname.sty, tree-dvips.sty, latexsym.sty, requires the new version of Late

Semantic Ambiguity and Perceived Ambiguity

I explore some of the issues that arise when trying to establish a connection between the underspecification hypothesis pursued in the NLP literature and work on ambiguity in semantics and in the psychological literature. A theory of underspecification is developed `from the first principles', i.e., starting from a definition of what it means for a sentence to be semantically ambiguous and from what we know about the way humans deal with ambiguity. An underspecified language is specified as the translation language of a grammar covering sentences that display three classes of semantic ambiguity: lexical ambiguity, scopal ambiguity, and referential ambiguity. The expressions of this language denote sets of senses. A formalization of defeasible reasoning with underspecified representations is presented, based on Default Logic. Some issues to be confronted by such a formalization are discussed.Comment: Latex, 47 pages. Uses tree-dvips.sty, lingmacros.sty, fullname.st

Some "PPIs" are just hyper-existentials

This paper shows that the French indefinite pronouns (quelqu'un, quelque chose) are neither PPIs (Baker 1970), nor double NPIs (Szabolcsi 2004). It claims that the scope restrictions involving negation and the impossibility to get a generic interpretation of these items, can only be explained by assuming that they have a strong vocation for existential readings, which can be seen as a qualified come-back to Russell's (1905) view. The paper establishes that this preference is a lexical property of the French determiner quelqu-

Quantification and polarity: negative adverbial intensifiers ('never ever', 'not at all', etc.) in Hausa

Hausa has a typologically interesting but poorly understood set of quantifying time and degree adverbs—equivalent to English 'never ever', 'not at all', etc.—which behave as negative polarity items and enhance the pragmatic impact of a negative utterance (both verbal and non-verbal). The functional distribution of these adverbial intensifiers is unusual, however, in that some are "bipolar", i.e., they can express opposite (minimal/maximal) values according to whether they occur in negative or positive syntactic environments, with the minimal intensifiers operating at the negative pole. An intensifier such as dàɗai, for example, can mean either 'never' (negative) or 'always' (positive), and other modifiers, e.g., atàbau, can express these same temporal meanings in addition to 'absolutely'. This paper provides a unified account of this natural functional class of adverbs, and is seen as a contribution to cross-linguistic research into polarity items and their licensing contexts

Incremental Interpretation: Applications, Theory, and Relationship to Dynamic Semantics

Why should computers interpret language incrementally? In recent years psycholinguistic evidence for incremental interpretation has become more and more compelling, suggesting that humans perform semantic interpretation before constituent boundaries, possibly word by word. However, possible computational applications have received less attention. In this paper we consider various potential applications, in particular graphical interaction and dialogue. We then review the theoretical and computational tools available for mapping from fragments of sentences to fully scoped semantic representations. Finally, we tease apart the relationship between dynamic semantics and incremental interpretation.Comment: Procs. of COLING 94, LaTeX (2.09 preferred), 8 page