Word Perfect or Postscript

Discontinuity

Richard Hudson, UCL


Bibliographical information

This version was written in September 1999, for publication in a special issue of 'Traitement Automatique des Langues' on dependency analysis, being edited by Sylvain Kahane. It is closely based on a version written in 1996, but never previously published. This in turn was an expansion of a 1994 paper, 'Discontinuous phrases in dependency grammar' (UCL Working Papers in Linguistics 6, 89-124).

Abstract

One of the most basic facts about sentence structure is that phrases generally have to be continuous - i.e. not interrupted by material from outside them; another fact is the existence of constructions in which phrases are allowed to be discontinuous - for example, raising, extraction and extraposition, and also coordination. The paper explains how these facts can be handled in terms of dependency structures by means of a number of very general principles of dependency structure. The dependency theory assumed is Word Grammar, in which discontinuous structures all involve multiple dependencies - one word which depends on more than one other word. The multiple dependencies can be divided between a ‘surface structure', in which discontinuity is not allowed (thanks to the No-Tangling Principle), and an ‘extra' structure in which it is. This system is in general equivalent to phrase-structure based analyses which allow structure sharing or transformations, but it has some empirical advantages. One such advantage is the possibility of explaining why adverb-preposing is not possible in subordinate interrogatives (*I know tomorrow what we shall do) although it is possible in main interrogatives. The paper also presents a parsing algorithm which exploits the general principles of dependency structure, and shows how the principles may be motivated functionally by their effects on the parsing process.

One of the most basic facts about sentence structure is that phrases generally have to be continuous - i.e. not interrupted by material from outside them; another fact is the existence of constructions in which phrases are allowed to be discontinuous - for example, raising, extraction and extraposition, and also coordination. The paper explains how these facts can be handled in terms of dependency structures by means of a number of very general principles of dependency structure. The dependency theory assumed is Word Grammar, in which discontinuous structures all involve multiple dependencies - one word which depends on more than one other word. The multiple dependencies can be divided between a 'surface structure', in which discontinuity is not allowed (thanks to the No-Tangling Principle), and an 'extra' structure in which it is. This system is in general equivalent to phrase-structure based analyses which allow structure sharing or transformations, but it has some empirical advantages. One such advantage is the possibility of explaining why adverb-preposing is not possible in subordinate interrogatives (*I know tomorrow what we shall do) although it is possible in main interrogatives. The paper also presents a parsing algorithm which exploits the general principles of dependency structure, and shows how the principles may be motivated functionally by their effects on the parsing process