Compiling and Using Finite-State Syntactic Rules

Proceeding volume: 1A language-independent framework for syntactic finlte-state parsing is discussed. The article presents a framework, a formalism, a compiler and a parser for grammars written in this forrealism. As a substantial example, fragments from a nontrivial finite-state grammar of English are discussed. The linguistic framework of the present approach is based on a surface syntactic tagging scheme by F. Karlsson. This representation is slightly less powerful than phrase structure tree notation, letUng some ambiguous constructions be described more concisely. The finite-state rule compiler implements what was briefly sketched by Koskenniemi (1990). It is based on the calculus of finite-state machines. The compiler transforms rules into rule-automata. The run-time parser exploits one of certain alternative strategies in performing the effective intersection of the rule automata and the sentence automaton. Fragments of a fairly comprehensive finite-state granmmr of English are presented here, including samples from non-finite constructions as a demonstration of the capacity of the present formalism, which goes far beyond plain disamblguation or part of speech tagging. The grammar itself is directly related to a parser and tagging system for English created as a part of project SIMPR I using Karlsson's CG (Constraint Grammar) formalism.Peer reviewe

Rapid Development of Morphological Descriptions for Full Language Processing Systems

I describe a compiler and development environment for feature-augmented two-level morphology rules integrated into a full NLP system. The compiler is optimized for a class of languages including many or most European ones, and for rapid development and debugging of descriptions of new languages. The key design decision is to compose morphophonological and morphosyntactic information, but not the lexicon, when compiling the description. This results in typical compilation times of about a minute, and has allowed a reasonably full, feature-based description of French inflectional morphology to be developed in about a month by a linguist new to the system.Comment: 8 pages, LaTeX (2.09 preferred); eaclap.sty; Procs of Euro ACL-9

Morphological Productivity in the Lexicon

In this paper we outline a lexical organization for Turkish that makes use of lexical rules for inflections, derivations, and lexical category changes to control the proliferation of lexical entries. Lexical rules handle changes in grammatical roles, enforce type constraints, and control the mapping of subcategorization frames in valency-changing operations. A lexical inheritance hierarchy facilitates the enforcement of type constraints. Semantic compositions in inflections and derivations are constrained by the properties of the terms and predicates. The design has been tested as part of a HPSG grammar for Turkish. In terms of performance, run-time execution of the rules seems to be a far better alternative than pre-compilation. The latter causes exponential growth in the lexicon due to intensive use of inflections and derivations in Turkish.Comment: 10 pages LaTeX, {lingmacros,avm,psfig}.sty, 1 figure, 1 bibtex fil