TUTORIAL ABSTRACTS 
Introduction to Computational Linguistics 
Ralph Grishman, New York University 
This tutorial provides a general overview of computational 
linguistics. Topics to be considered include the components 
of a natural language processing system; syntax analysis 
(including context-free grammars, augmented context-free 
grammars, grammatical constraints, and sources of syntactic 
ambiguity); semantic analysis (including meaning represen- 
tation, semantic constraints, quantifier analysis); and dis- 
course analysis (identifying implicit information, establishing 
text coherence, frames, and scripts). Examples will be drawn 
from various application areas, including database interface 
and text analysis. 
Natural Language Generation 
Kathleen McKeown, Columbia University 
In this tutorial, we will begin by identifying the types of deci- 
sions involved in language generation and how they differ 
from problems in the interpretation of natural language. 
Several techniques that have been used for "surface" genera- 
tion (i.e., determining the syntactic structure and vocabulary 
of the generated text) will be examined, including grammars, 
dictionaries, and templates. From there, we will move on to 
other problems in language generation, including how the 
system can decide what to say in a given situation and how 
it can order the information for inclusion in a text. Here we 
will study the constraints that have been used for these deci- 
sions in domains such as expert systems, database systems, 
scene description, and problem solving. We will also look at 
the interaction between conceptual decisions such as these 
and decisions in surface generation, considering approaches 
that propose an integrated solution. 
Structuring the Lexicon 
Robert Ingria, BBN Laboratories Incorporated 
This tutorial will discuss the information that has been 
stored in the lexicon. It will first deal with the types of in- 
formation that have typically been placed in lexical entries, 
detailing what sorts of lexical information is necessary for 
natural language systems. The format of lexical entries and 
the relationships between lexical entries will be considered 
next (as in cases of irregularly inflected forms, such "go", 
"went", "gone", abbreviations and acronyms, such as "helo" 
and "helicopter", and derived forms, such as "destroy" and 
"destruction"). Alternate places for storing information will 
also be considered (for example, regular morphological infor- 
mation might be contained in individual lexical er~tries or in 
the grammar). The tutorial will conclude with the implica- 
tions of recent work in linguistic theory for the structure of 
lexicons for computational purposes. 
Recent Developments In Syntactic Theory and Their 
Computational Import 
Anthony S. Kroch, University of Pennsylvania 
Syntactic frameworks currently under development in linguis- 
tics take different perspectives on several issues of computa- 
tional interest. Among these are: (1) the importance of stat- 
ing linguistic theories in a well-defined and explicit formalism 
whose mathematical properties are known or investigable; (2) 
the degree to which the syntatic properties of sentences can 
be understood independently of their semantic interpretation; 
and (3) the extent to which empirical and mathematical 
results on parsing and generation can illuminate linguistic 
issues. We shall discuss the perspectives on these and related 
questions held by various current linguistic theories, including 
generalized phrase structure grammar (GPSG), government 
binding theory (GB), lexical-functional grammar (LFG), and 
tree adjoining grammar (TAG). 
Current Approaches to Natural Language Semantics 
Graeme Hirst, University of Toronto 
This tutorial provides a survey of various computational ap- 
proaches to semantics--the process of determining the mean- 
ing of a sentence or other utterance. Issues addressed will 
include definitions of meaning; the differences between lin- 
guistic theories of semantics and formalisms suitable for com- 
putational understanding of language; knowledge represen- 
tations that suitable for representing linguistic meaning; the 
relationship between semantic processing and syntactic pars- 
ing; and factors in choosing a semantic formalism for a par- 
ticular computational application. The approaches to seman- 
tics that will be discussed will include procedural semantics, 
conceptual dependency, Montague semantics, and composi- 
tional and knowledge-based approaches. 
Machine Translation 
Sergei Nirenburg, Colgate University 
This tutorial will address the recent resurgence of interest in 
machine translation (MT) in the United States, Europe, and 
Japan. Topics to be discussed include the variety of objec- 
tives for MT systems; various research and developments 
methodologies; MT as an application area for theoretical lin- 
guistics, computational linguistics, and artificial intelligence; 
environments for MT research; and selected case studies of 
research projects. 
