IRCS Technical Reports Series

Document Type

Technical Report

Date of this Version

August 1998


University of Pennsylvania Institute for Research in Cognitive Science Technical Report No. IRCS-98-18.


This document describes a sizable grammar of English written in the TAG formalism and implemented for use with the XTAG system. This report and the grammar described herein supersedes the TAG grammar described in [XTAG-Group,1995]. The English grammar described in this report is based on the TAG formalism developed in [Joshi et al., 1975], which has been extended to include lexicalization ([Schabes et al., 1998]) and unification-based feature structures ([Vijay-Shanker and Joshi, 1991]). The range of syntactic phenomena that can be handled is large and includes auxiliaries (including inversion), copula, raising and small clause constructions, topicalization, relative clauses, infinitives, gerunds, passives, adjuncts, it-clefts, wh-clefts, PRO constructions, noun-noun modifications, extraposition, determiner sequences, genitives, negation, noun-verb contractions, sentential adjuncts and imperatives. This technical report corresponds to the XTAG Release 8/31/98. The XTAG grammar is continuously updated with the addition of new analyses and modification of old ones, and an online version of this report can be found at the XTAG web page:



Date Posted: 20 August 2006