Dan Flickinger

On building a more efficient grammar by exploiting types

Modern grammar development platforms often support multiple devices for representing properties of a natural language, giving the grammar writer some freedom in implementing analyses of linguistic phenomena. These design alternatives can have dramatic consequences for efficiency both in processing and in grammar building. In this paper I report on three experiments in making systematic modifications to a broad-coverage grammar of English in order to gain efficiency without loss of linguistic elegance. While the experiments are to some degree both platform-dependant and theory-bound, the kinds of modifications reported should be applicable to any unification-based grammar which makes use of types. The results make a strong case for a more visible role for the linguist in the collaborative effort to achieve greater processing efficiency.

The grammar matrix: an open-source starter-kit for the rapid development of cross-linguistically consistent broad-coverage precision grammars

The grammar matrix is an open-source starter-kit for the development of broad-coverage HPSGs. By using a type hierarchy to represent cross-linguistic generalizations and providing compatibility with other open-source tools for grammar engineering, evaluation, parsing and generation, it facilitates not only quick start-up but also rapid growth towards the wide coverage necessary for robust natural language processing and the precision parses and semantic representations necessary for natural language understanding.

An Algebra for Semantic Construction in Constraint-based Grammars

We develop a framework for formalizing semantic construction within grammars expressed in typed feature structure logics, including HPSG. The approach provides an alternative to the lambda calculus; it maintains much of the desirable flexibility of unification-based approaches to composition, while constraining the allowable operations in order to capture basic generalizations and improve maintainability.

The LinGO Redwoods treebank motivation and preliminary applications

The LinGO Redwoods initiative is a seed activity in the design and development of a new type of treebank. While several medium- to large-scale treebanks exist for English (and for other major languages), pre-existing publicly available resources exhibit the following limitations: (i) annotation is mono-stratal, either encoding topological (phrase structure) or tectogrammatical (dependency) information, (ii) the depth of linguistic information recorded is comparatively shallow, (iii) the design and format of linguistic representation in the treebank hard-wires a small, predefined range of ways in which information can be extracted from the treebank, and (iv) representations in existing treebanks are static and over the (often year- or decade-long) evolution of a large-scale treebank tend to fall behind the development of the field. LinGO Redwoods aims at the development of a novel treebanking methodology, rich in nature and dynamic both in the ways linguistic data can be retrieved from the treebank in varying granularity and in the constant evolution and regular updating of the treebank itself. Since October 2001, the project is working to build the foundations for this new type of treebank, to develop a basic set of tools for treebank construction and maintenance, and to construct an initial set of 10,000 annotated trees to be distributed together with the tools under an open-source license.

SemEval 2015 Task 18: Broad-Coverage Semantic Dependency Parsing

Task 18 at SemEval 2015 defines Broad-Coverage Semantic Dependency Parsing (SDP) as the problem of recovering sentence-internal predicate–argument relationships for all content words, i.e. the sema ...

HPSG Analysis of English

In this chapter we summarize the results of the HPSG English grammar project for analysis and generation in Verbmobil, housed at CSLI, Stanford University. After providing a description of the design and implementation of the grammar, we give an overview of the linguistic phenomena encountered in the Verbmobil domains, show the results of an evaluation of the grammar measured against transcribed spoken language data, and then point to next steps in the development of the grammar.

In Search of a Systematic Treatment of Determinerless PPs

This paper examines Determinerless PPs in English from a theoretical perspective. We classify attested P + N combinations across a number of analytic dimensions, arguing that the observed cases fall into at least three distinct classes. We then survey three different analytic methods that can predict the behaviour of the differing classes and examine various remaining difficult cases that may remain as challenges.

Introduction to this Special Issue

This issue of Natural Language Engineering journal reports on recent achievements in the domain of HPSG-based parsing. Research groups at Saarbrucken, CSLI Stanford and the University of Tokyo have worked on grammar development and processing systems that allow the use of HPSG-based processing in practical application contexts. Much of the research reported here has been collaborative, and all of the work shares a commitment to producing comparable results on wide-coverage grammars with substantial test suites. The focus of this special issue is deliberately narrow, to allow detailed technical reports on the results obtained among the collaborating groups. Thus, the volume cannot aim at providing a complete survey on the current state of the field. This introduction summarizes the research background for the work reported in the issue, and puts the major new approaches and results into perspective. Relationships to similar efforts pursued elsewhere are included, along with a brief summary of the research and development efforts reflected in the volume, the joint reference grammar, and the common sets of reference data.

Parallel distributed grammar engineering for practical applications

Based on a detailed case study of parallel grammar development distributed across two sites, we review some of the requirements for regression testing in grammar engineering, summarize our approach to systematic competence and performance profiling, and discuss our experience with grammar development for a commercial application. If possible, the workshop presentation will be organized around a software demonstration.

Deep open-source machine translation

This paper summarizes ongoing efforts to provide software infrastructure (and methodology) for open-source machine translation that combines a deep semantic transfer approach with advanced stochastic models. The resulting infrastructure combines precise grammars for parsing and generation, a semantic-transfer based translation engine and stochastic controllers. We provide both a qualitative and quantitative experience report from instantiating our general architecture for Japanese–English MT using only open-source components, including HPSG-based grammars of English and Japanese.