06.06.2008 FLATLANDS 2008 1

Kakia Chatsiou Modern Greek Grammar fragment Implementation using XLE

GreekGramReporting on the progress of the implementation of a Modern Greek Grammar Fragment using the

XLE parser

Kakia Chatsiouachats@essex.ac.uk

Dept of Language and LinguisticsUniversity of Essex

Parts of this project have been funded with an ESRC Award PTA-2004-031-00112 , support which is gratefully acknowledged.

Previous versions of this report have been presented at the LangUE 2007 International Postgraduate Conference and the Language and Computation Day 2007, University of Essex.

Kakia Chatsiou Modern Greek Grammar fragment Implementation using XLE

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Outline

• Introduction – Overview of the ParGram Project– Project Objectives– Participating Members– The XLE Platform– Grammar Architecture

• The GreekGram Project– Overview– Assumptions– Coverage– Demonstration– Future Development Directions

Kakia Chatsiou Modern Greek Grammar fragment Implementation using XLE

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Outline

• Introduction – Overview of the ParGram Project– Project Objectives– Participating Members– The XLE Platform– Grammar Architecture

• The GreekGram Project– Overview– Assumptions– Coverage– Demonstration– Future Development Directions

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An Overview of the ParGram Project

Project Objectives

• Broad coverage grammars– Inclusion of important and frequently occurring constructions– Linguistically motivated analyses

• Parallel and crosslinguistic development of grammars between the participating members– All grammars are guided by a common set of linguistic principles

and a commonly agreed upon set of grammatical analyses and features

– Identical treatment of core crosslinguistic phenomena

• Methods in grammar engineering– Common test methods and evaluation strategies– Balance between efficiency, performance, reliability and

maintainability across grammars

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Participating Members

An Overview of the ParGram Project

PARC, CAChinese, English,

French

EssexGreek, Welsh

ManchesterArabic

OxfordMalagasy

DCU, IrelandChinese, English, French, German,

Japanese, Spanish

Fuji XEROXJapanese

Bergen, NorwayGeorgian, Norwegian, Tigrinya

Ho Chi MinchVietnamese

DebrecenHungarian

IMS, StuttgartGerman

KonstanzUrdu

Sabanci, IstanbulTurkish

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An Overview of the ParGram Project

The Xerox Linguistics Environment (XLE) Platform

• Under current development at PARC (Palo Alto Research Center, USA)

• An implementation of the Lexical Functional Grammar (LFG) Formalism

• Implemented in C; works in Unix, Linux, MacOS. MS Windows version under development.

• Integrates a morphological analyser employing Finite State Technology

• Can be used for both parsing and generation• Includes tools for various grammar development activities (such

as analysing performance, test-suites)• The core technology used in the consumer search engine based

on natural language processing which is currently under development by

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An Overview of the ParGram Project

• a Silicon Valley Company, currently building a transformative consumer search enginesearch engine based on natural language processing:– It is based on technologies that take advantage of the structure and

nuances of natural language– It offers an innovative approach to searching:

• It breaks the confines of keyword search queries using both keywords, short phrases and natural language

• Makes search more natural and intuitive• Aims at fundamentally changing how we search the web and at the same

time delivering higher quality results• currently searching Wikipedia with the help of FreeBase as the semantic

knowledge database

(source: http://www.powerset.com )

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Kakia Chatsiou Modern Greek Grammar fragment Implementation using XLE

Search Engine Demo

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Kakia Chatsiou Modern Greek Grammar fragment Implementation using XLE

Demo – sample queries

• Who is Indiana Jones?• Which are the films that Spielberg directed?• I am looking for Van Gogh’s paintings• Paintings by Van Gogh• Albums by westlige• Books by Charles Dickens

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Kakia Chatsiou Modern Greek Grammar fragment Implementation using XLE

The XLE parser interface

Kakia Chatsiou Modern Greek Grammar fragment Implementation using XLE

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An Overview of the ParGram Project

Basic Grammar Architecture

Other Finite State Tools

Tokenizer

Morpholo-gical

AnalyserFST

Lexicon(s)(Hand-written

OrAutomatically

Extracted)

LFG Grammar

(rules, templates)

Grammar Resources(parsing

and generating)

Kakia Chatsiou Modern Greek Grammar fragment Implementation using XLE

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Outline

• Introduction – Overview of the ParGram Project– Project Objectives– Participating Members– The XLE Platform– Grammar Architecture

• The GreekGram Project– Overview– Assumptions– Coverage– Demonstration– Future Development Directions

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The GreekGram Project

Overview

• A preliminary effort to develop a large-scale LFG computational Grammar for Modern Greek

• Shares the objectives and principles of similar ParGram projects (parallel and crosslinguistic; balancing of maintainability and achieving large coverage)

• Current main focus is on development of grammar rules and syntactic phenomena relevant to my thesis; the lexicon is kept as minimal as possible

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The GreekGram Project

Assumptions

• Focus on syntax (but in such a way that the representations produced could serve as direct and useful input for incorporation into semantic interpretations)

• All four possible Modern Greek Word orders are treated as equally acceptable in terms of markedness and acceptability

• Modern Greek word Order is represented non-configurationally (Tzanidaki, 1996; Alexopoulou, 1999)

• No treatment of morphology (using the Morphological analyzer or some other Finite state tool) – there is a separate lexical entry for each form.

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The GreekGram Project

Coverage

• All 4 possible word orders (irrespective of markedness)• Pro-drop character of the language• Subcategorisation frames of intransitive, transitive and

ditransitive verbs• Number, case and gender agreement within the NP or PP;

subject-verb agreement• Basic Relative Clause structure• Coordination of relative clauses• Some punctuation

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The GreekGram Project

Demonstration

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The GreekGram Project

Future Development Directions

• Account for a greater variety of verb subcategorisation frames

• Enrich the lexicon adding more lexical entries• Account for the morphology within the lexicon, using the

XFST (or other finite state tools)• Expand the coverage of the grammar to other constructions

such as interrogatives, imperatives and negation• …

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Kakia Chatsiou Modern Greek Grammar fragment Implementation using XLE

Thank you!

For more information and updates on the progress of the project visit

http://privatewww.essex.ac.uk/~achats/projects/greekgram/index.html