Review of The Oxford Handbook of Computational Linguistics
Date: Fri, 23 May 2003 15:16:01 +0200
From: Roland Stuckardt
Subject: Mitkov, ed. (2003) The Oxford Handbook of Computational Linguistics
Mitkov, Ruslan, ed. (2003) The Oxford Handbook of
Computational Linguistics, Oxford University Press.
Announced at http://linguistlist.org/issues/14/14-567.html
Roland Stuckardt, Johann Wolfgang Goethe University
Frankfurt am Main, Germany
DESCRIPTION OF THE BOOK
The edited collection under review, the Oxford Handbook of
Computational Linguistics (OHCL), belongs to the Oxford
Handbooks series, which, according to the publisher, aims
at providing "an authoritative and state-of-the-art survey
of current thinking and research" in particular subject
areas. According to the editor, the OHCL addresses
university researchers, teachers, and students in the
fields of Computational Linguistics, Computer Science and
Linguistics, as well as professionals such as industrial
researchers, executives, software engineers, and
The book consists of thirty-eight chapters authored by
fifty experts from all over the world, and a preface by
Martin Kay with a brief description of the history of the
discipline of Computational Linguistics (CL). Each chapter
covers a particular topic of CL. Chapter lengths vary
between eleven and twenty-nine pages, with the majority of
chapters comprising between fifteen and twenty pages.
Access to the individual chapters is facilitated by
abstracts. Each chapter includes a local list of
bibliographic references, hints at further reading, and
pointers (in particular, URLs) to relevant resources
(software, corpora etc.).
The OHCL is divided into three parts, which are intended
to reflect a natural progression from theory to practice.
Part I, "Fundamentals", considers the issues typically
covered by an introductory text on general linguistics,
corresponding to the various levels of linguistic
abstraction: 1. Phonology, 2. Morphology, 3. Lexicography,
4. Syntax, 5. Semantics, 6. Discourse, and 7. Pragmatics
and Dialogue. However, the topics are discussed from a
computational perspective to develop an understanding of
the specific problems to be solved before a respective
software technology can be implemented. Two further
chapters, 8. Formal Grammars and Languages, and 9.
Complexity, provide relevant background material of
mathematical linguistics and theoretical computer science,
covering, in particular, the fundamentals of automata
theory, formal languages, and computational complexity.
Part II, "Processes, Methods, and Resources", takes the
computation-oriented discussion of the linguistic and
mathematical fundamentals in part I as the point of
departure. The following detailed description of the basic
stages of text and speech processing and the employed
methods, resources, and formalisms goes one step ahead
towards automatic natural language processing (NLP). Eight
chapters deal with specific problems of processing written
and spoken language: 10. Text Segmentation, 11. Part-of-
Speech Tagging, 12. Parsing, 13. Word-Sense Disambiguation
14. Anaphora Resolution, 15. Natural Language Generation,
16. Speech Recognition, and 17. Text-to-Speech Synthesis.
Another nine chapters describe the most important general
methods, resources, and formalisms employed in these
processing stages: 18. Finite-State Technology, 19.
Statistical Methods, 20. Machine Learning, 21. Lexical
Knowledge Acquisition, 22. Evaluation, 23. Sublanguages
and Controlled Languages, 24. Corpus Linguistics, 25.
Ontologies, and 26 Tree-Adjoining Grammars.
Part III, "Applications", focuses on the application of
NLP technology for solving real world problems, proceeding
from the description of the NLP base technology that is
provided in part II. Part III comprises twelve chapters:
27. Machine Translation: General Overview, 28. Machine
Translation: Latest Developments, 29. Information
Retrieval, 30. Information Extraction, 31. Question
Answering, 32. Text Summarization, 33. Term Extraction and
Automatic Indexing, 34. Text Data Mining, 35. Natural
Language Interaction, 36. Natural Language in Multimodal
and Multimedia Systems, 37. Natural Language Processing in
Computer-Assisted Language Learning, and 38. Multilingual
On-Line Natural Language Processing.
In addition, the OHCL provides a list of commonly used
acronyms and a glossary with brief definitions of about
sixhundred key terms of CL and NLP. There are two general
indexes: one by subject, and one by author/person.
It would be beyond the scope of this review to provide a
detailed evaluation of each of the thirty-eight chapters.
Thus, the OHCL will be commented on at a general level. To
some specific subjects it will be looked at in detail.
The above description clearly shows that the OHCL covers
all main topics of CL. It deals with the whole range of
text, speech, and dialogue processing, and discusses
issues of text and speech analysis as well as generation.
The OHCL is unique in that it bridges between the
linguistic fundamentals (as provided in part I), the
respective software base technology (as described in part
II), and possible applications (as discussed in part III).
As such it complements the recent textbook by Jurafsky and
Martin (2000), which focuses on the algorithmic,
mathematical, and engineering aspects of NLP. Another
positive aspect is the inclusion of brief and quite
comprehensive surveys of the most central methods,
resources, and formalisms, such as machine learning,
statistics, finite-state technology, and corpora.
The general organization of the handbook is excellent. In
many cases, multi-authored volumes consist of collections
of more or less loosely connected articles. Regarding the
OHCL, editorial efforts concerning the overall coherence
have been highly successful, resulting in self-contained
chapters that provide a large number of useful cross-
references that foster the connectivity of the material.
Coherence and general accessibility are enhanced by the
uniform style of presentation, which enables the reader to
quickly access the relevant resources and further readings
without skimming through the whole body of text.
Content quality and actuality of the individual chapters
are generally high, fostered by the selection of authors
that are world-leading experts with extensive research
experience on the respective topics. However, the
assignment of multiple authors also entails a certain
variance in the formal (organizational and presentational)
quality of the individual contributions and, more
importantly, in the accessibility for different types of
readers. It goes without saying that tight page limits
always involve a trade-off between coverage on one and
verbosity and readability on the other hand. Regarding the
OHCL, with respect to both accessibility and formal
quality, the difference between the individual articles is
considerable, which may only partly be attributed to the
varying degree of complexity of the issues covered.
Beginning with the positive side of the gamut, the
majority of chapters is of high organizational and
presentational quality, and accessible, with reasonable
efforts, for advanced students, scientists, and
professionals with moderate previous knowledge of CL, NLP,
or Linguistics. Among the many excellently written
chapters are: 2. Morphology, 3. Lexicography, 7.
Pragmatics and Dialogue, 10. Text Segmentation, 15.
Natural Language Generation, 25. Ontologies, 27. Machine
Translation: General Overview, 28. Machine Translation:
Latest Developments, 29. Information Retrieval, 34. Text
Data Mining, 35. Natural Language Interaction, 37. NLP in
Computer-Assisted Language Learning.
However, there is also room for further improvement. In
part I, "Fundamentals", for instance, the strong direction
of chapter 2 (Morphology) towards computational issues is
in line with the computational perspective to be assumed.
Some other articles, however, are to a lesser extent, such
as the overall excellent chapter 5 on computational
semantics, which could be further enhanced by an
assessment of the general computational feasibility of the
construction of compositional-semantic descriptions, their
expected coverage, and their potential contribution to
robust NLP. More importantly, the presentation and
organization of the material covered by chapters 8 (Formal
Grammars and Languages) and 9 (Complexity) should be
revised. While these articles are useful references for
researchers with previous knowledge, their presentation
may be in parts too dense for an audience unfamiliar with
these rather mathematical issues. The author of the last-
mentioned chapter himself admits: "For a true
understanding of complexity, it is best to read a serious
algorithms book [?]." (page 196). Since the topics covered
in these two chapters are highly related, it may be
reasonable to integrate them into a single chapter of
forty to fifty pages. To enhance the coherence of this
rather formal subject matter with the rest of the book,
the important discussion of its implications for practical
issues of NLP may be expanded; the respective material,
which is currently scattered about various subsections
(e.g., 9.2.6 and 9.3.8), should be put into a dedicated
Regarding part II, "Processes, Methods, and Resources",
parts of the generally well-written chapter 16 on speech
recognition may be considered as quite difficult to
access. Section 16.2 (Acoustic Parameterization and
Modeling) refers to advanced technical notions and
presupposes a quite high amount of previous knowledge. On
the other hand, it misses out some fundamentals, e.g. the
notion of formants, which play a central role in the
analysis of waveforms, and which are not included in the
glossary either (cf. Jurafsky and Martin (2000), which
provides a more extensive discussion of this topic).
However, the other sections of this chapter are readily
accessible without expert knowledge; in particular, the
discussion of the performance of state-of-the-art speech
recognition technology is excellent.
Regarding part III, "Applications", chapter 31 on question
answering might be, to a certain extent, enhanced. While
this article is logically structured and well organized,
some parts of the presentation may be perceived as too
dense, particularly section 31.7 on answer extraction. The
details on training a perceptron, in particular the
formula for the computation of a relative comparison score
and the empirically determined weights and threshold
values, are of little value to a reader interested in the
fundamentals of answer extraction. Instead, more room
should be given to the discussion of the principal ideas
of answer extraction methods, perhaps focusing on the two
most promising approaches and referring the reader to the
literature for further technical details.
There is an additional topic further editions of the OHCL
should include: discourse parsing. Fostered in large parts
by the seminal work of Marcu (2000), this subject area has
made rapid progress in the last few years. A chapter on
algorithmic approaches to discourse parsing would neatly
fit in the book and supplement the current edition?s
single article on discourse in part II (14. Anaphora
Resolution). As such, it would provide a natural link
between chapter 6 on the linguistic fundamentals of
discourse and important applications discussed in part
III, in particular text summarization (chapter 32, which
explicitly refers to Marcu?s work). Moreover, part III
might be enhanced if chapters on text categorization and
internet search engines were included.
There are some further minor content-related issues.
Chapter 14 (Anaphora Resolution) should include a brief
discussion of the intricacies of anaphor and ellipsis
resolution in dialogue; this important issue is referred
to in chapter 35 on natural language interaction. Chapter
20 on machine learning should include approaches of
unsupervised learning, which receive increasing attention
in NLP since supervised learning requires annotated
corpora the gathering of which is, in general, expensive.
Chapter 22 on the central topic of evaluation should be
allotted more pages. Some practical examples of formal,
corpus-based evaluation tasks would be helpful.
Furthermore, the comparatively dense section 22.4 on the
evaluation of interactive systems should include more
details. Chapter 30 on information extraction should
provide more pointers to concrete systems, including an
overview of software technology available for different
languages. Finally, chapter 35 on natural language
interaction should include a discussion on the emerging
dialogue modeling standard VoiceXML.
Two further marginal organizational issues: the table of
contents should provide at least the section headings in
addition to the chapter headings. Chapter 2 employs five
different levels of section embedding; this is inadequate
with an article of only 23 pages.
In accordance with the intentions set out by the editor
and the publisher, the OHCL provides a comprehensive high-
quality survey of the theoretical fundamentals of CL and
state-of-the-art NLP, as it covers the base technology,
the underlying methods, and a wide range of application
scenarios. Most chapters provide self-contained surveys of
specific CL topics that are adequate reading to an
audience with moderate previous knowledge, ranging from
advanced students of CL, Linguistics, and Computer Science
to scientists and industrial researchers. While it neither
substitutes introductory textbooks nor monographs on the
issues under discussion, it is an excellent reference book
that provides a wealth of information and enables the
experienced reader to quickly enter into new subject areas
of CL and NLP. Thanks to its unique structure, it neatly
complements books that focus on the technological aspects
of NLP such as the text of Jurafsky and Martin (2000).
Whereas these authors provide more thorough descriptions
and illustrations of algorithms, the particular strengths
of the OHCL are the comprehensive computation-oriented
discussion of the fundamental linguistic issues and the
broad coverage of NLP methods and resources. It thus
extensively accounts for the theoretical and
methodological backgrounds of CL and NLP.
A final note on pricing: the relatively high price of GBP
95.- (US$ 150.-) quoted by the publisher may put off many
potential readers. The publisher should consider issuing a
moderately priced student?s edition to make the OHCL
affordable to the wide audience it definitely deserves.
Daniel Jurafsky and James H. Martin (2000). Speech and
Language Processing. An Introduction to Natural Language
Processing, Computational Linguistics, and Speech
Recognition. Prentice Hall, Upper Saddle River, NJ.
Daniel Marcu (2000). The Theory and Practice of Discourse
Parsing and Summarization. The MIT Press, Cambridge, MA.
| ABOUT THE REVIEWER:
ABOUT THE REVIEWER Roland Stuckardt works as a postdoctoral researcher and consultant in the fields of Computational Linguistics and Natural Language Engineering. He received his Ph.D. in 2000 from the University of Frankfurt am Main. His current research interests include anaphor resolution, information extraction, text summarization, question answering, and spoken dialogue systems. (web: http://www.stuckardt.de/)