Introduction to Corpora and Corpus Linguistics COG

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Introduction to Corpora and Corpus Linguistics

• COGS 523-Lecture 1
• General Introduction

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Related Readings

• Course Pack
• Meyer (2002). Corpus Analysis and Linguistic
  Theory. Ch 1
• Abney (1996) Statistical Methods and Linguistics
• Extra Material (Entirely optional, part of the
  presentation draws on these material)
• McEnery and Wilson (2001) Ch1
• McEnery et al. (2006) A1 and B2
• Tognini-Bonelli (2001). Corpus Linguistics at
  Work. Ch 3
• Corpora Discussion List Archives Corpora
  Chomsky/Harris Discussion, April 2001
• BorsleyIngham vs Stubbs Discussion. Lingua 112
  (2002)
• Schönefeld (1999) Corpus Linguistics and
  Cognitivism, International Journal of Corpus
  Linguistics 4(1)

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What is a Corpus?
Derlem (alt. Bütünce)
Text/Speech/ Video
Annotation

Digital media
Written/Spoken Language
Design Criteria
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Questions of the Week

• Is working with corpora a methodology within
  linguistics or a distinctive subfield (corpus
  linguistics)?
• What potential is there for empirical analysis of
  corpora to contribute to linguistic theory?
• What are the dangers involved in corpus-based
  linguistics? How can these dangers be reduced?

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What is a Corpus,again?

• A body of written text or transcribed speech
  which can serve as a basis for linguistic
  analysis or description, designed or required for
  a particular representative function.
• An electronic collection of texts in a uniform
  representation
• Corpus vs text archive vs database

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Sinclairs definition

• A corpus is a collection of pieces of language
  that are selected and ordered according to
  explicit linguistic criteria in order to be used
  as sample of language

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Should a Corpus be Necessarily

• Large?
• Be authentic?
• Compiled for linguistic analysis?
• Be saturated in terms of lexical growth?
• Be representative?
• Be machine readable?

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A History of Corpora

• Pre-computers era (pre 60s)
• Transition era (60s to beginning of 90s)
• Maturation era (90s onwards)
• What did technology bring?
• Increased accuracy, speed, accountability,
  replicability, large volumes of better annotated
  data.

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Phonology Morphology Lexicon Syntax Semantics Disc
ourse Pragmatics
Introspection Experimental Methods Formal
Linguistic Analysis Computational Modeling Corpus
Based Methods?
Linguistics
Computational Linguistics Psycholinguistics Sociol
inguistics Historical Linguistics Applied
Linguistics Corpus Linguistics ?
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Corpus Linguistics

• The term emerged in 1980s, although the use of
  corpora has a long history.
• Modern perspectives contain a number of opposing
  positions.

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Linguistic Subdisciplines with a tradition for
corpora

• Historical Linguistics
• Phonetics
• Language Acquisition
• Statistical Natural Language Processing/Language
  Engineering/Computational Linguistics

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Corpus Linguistics a Methodology, Theory, or
Subfield of Linguistics?

• Rationalism vs Empiricism
• Formalists vs Functionalists
• Competence vs Performance
• Core vs Periphery
• Applied Linguistics vs Theoretical Linguistics
• Corpus-Based vs Corpus-Driven Approaches
  (Tognini-Bonelli)

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False Assumptions

• All corpus linguists are descriptivists,
  interested only in counting and categorizing
  occurrences in a corpus, and that all generative
  grammarians are theoreticians unconcerned with
  the data on which their theories are based.
  Complexity of the structure is not in the
  interest of corpus linguist. (Meyer, 2002)

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Evaluating Linguistic Theories

• Observational vs explanatory vs descriptive
  adequacy
• Falsifiability, Completeness, Simplicity,
  Objectivity etc...

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Chomskyan quotes

• The corpus could never be a useful tool for the
  linguist, as the linguist must seek to model
  language
• Corpus Linguistics does not exist.
• Any natural corpus will be skewed and
  incomplete. Some sentences wont occur, because
  they are obvious, others because they are false,
  still others because they are impolite. The
  corpus, if natural, will be so wildly skewed that
  the description would be no more than a mere
  list.
• Indeed Chomsky contributed to modern view of
  corpus linguistics by improving language
  technology and to overcoming the
  structuralist-behaviourist views of language as
  something that could be enumerated, by way of
  formal language theory.

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Why Statistics help? (Abney)

• Language Acquisition
• Language Changes
• Language Variation
• Grammaticality- Ambiguity Computation
• Modularity is not in isolation

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Grammaticality Judgements

• He shines Tony books.
• He gives Tony books.
• If intutions do,why bother with corpus analysis?
• Artificial data is artificial and creates another
  kind of skewedness.
• Yes I could say that-but I never would
  gradedness in grammaticality judgements
• Intuitions are perceptions....

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Alternative Views

• Leech (92)
• Computer Corpus Linguistics is a new research
  enterprise, a new philosophical approach that
• Concentrates on linguistic performance
• Leads to a more empirical view of scientific
  inquiry
• Exploits qualitative as well as quantitative
  methodology to produce a quantitatively oriented
  language model such as Bayesian language models.
• Not everyone agrees!

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Further Remarks

• Corpus Linguistics contributed to blurring the
  distinction between grammar and lexicon.
• Sinclairs open choice vs idiom principle
• Cognitive linguists can accommodate data and
  facts revealed by corpus linguistic analysis

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Corpus Linguistics vs Corpus Based Linguistics

• There is no inherent incompatibility between
  theoretical generative linguistics and corpus
  linguistics (Seegmiller)
• Generative and corpus linguistics are two
  approaches to the same problem, and must meet
  somewhere. Generative theories should match or be
  backed up by real data. (Schiffrin)
• What is possible and what is probable? Corpus
  linguistics offers a way of describing things
  that we do regularly and frequently with
  greater confidence and reliability than by using
  introspection alone. (Krishnamurthy)

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Corpus-Based Linguistics vs Corpus-Driven
Linguistics

• Take existing theory as a starting point and
  correct and revise the theory in light of corpus
  evidence.

• Favour very large, full text corpora, with the
  idea of cumulative representativeness and no
  annotation-to be able to free oneself of
  preconceived theories.
• e.g collocations rather than colligations
• Without a corpus, there is no meaningful work to
  be done (attributed to Sinclair, Stubbs but see
  their own writings)

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Reconciling Views

• Corpora are excellent resources for verifying the
  falsifiability, completeness, simplicity,
  strength, and objectivity of linguistic
  hypotheses (Meyer, 2002).
• They can provide additional linguistic
  perspectives which improve our knowledge of
  language and our ability to use it (a weaker
  position)

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The Rise of Corpora
Years No of Corpus based studies
To 1965 10
1966-1970 20
1971-1975 30
1976-1980 80
1981-1985 160
1986-1991 320
(McEnery and Wilso, 2001)
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Range of Activities in Corpus-based Linguistics

1. Corpus Design, Compilation and Annotation
2. Developing Tools for (1) or Analysis of Corpora
3. Linguistic Studies or Applications using corpora
   developed in (1) using tools developed in (2)

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Types of Corpora

• General (typically balanced and made available
  for general linguistic use) vs Specialized
  (Dialect corpora,language acquisition
  corpora,learner corpora)
• Core Corpora
• Written vs Spoken Corpora
• Full-text vs Sample-text Corpora

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More Typology

• Finite-size (Static) vs Dynamic/Monitor Corpora
• Monolingual vs Multilingual Corpora (Parallel
  corpora, Comparable Corpora)
• Rather Graded Distinctions
• Raw vs Annotated,
• Balanced vs Pyramidal vs Opportunistic Corpora
• Synchronic vs Diachronic

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Some Examples of Corpora

• Pre-electronic corpora
• Biblical and Literary Studies
• Lexicographical
• Dialect Studies
• Language Education
• Grammatical
• Quirks Survey of English Usage Corpus (later
  computerized) had 200 samples of 5000 words each,
  half spoken, half written, tagged manually with
  65 grammatical features.

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More Examples

• Major Electronic Corpora
• Brown Corpus (Francis and Kucera, 1965) Brown
  University Standart Corpus of Present Day
  American English- 1 million words, 1961-64, 500
  samples of 2000 words each
• Lancaster-Oslo-Bergen Corpus (LOB corpus) a
  comparable corpus of British English fewer
  westerns exist,though!
• FBrown and FLOB comparable corpora of 1990s

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Major Electronic Corpora

• Also modeled after Brown
• Kolhapur Corpus of Indian English
• Wellington Corpus of New Zealand English...
• London-Lund Corpus (1975)- 100 5000-word samples
  of spoken data, major spoken corpus till mid
  1990s, predominantly highly educated adult
  speakers
• Lancaster/IBM Spoken Corpus (SEC)-better
  balance-11 categories,detailed prosodic annotation

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Major Electronic Corpora

• Longman Dictionary of Contemporary English
  (LDOCE) COBUILD Project-Bank of English-524
  million words as of 2004.
• International Corpus of English
• International Corpus of Learners English- 2M
  words- 500 word essays, different English
  backgrounds
• Longman Learners Corpus, HKUST Learners Corpus
• CHILDES Child Language Data Exchange System
• European Corpus Initiative ECI 93 million
  words
• Many corpora are available from LDC and
  ELDA/ELRA.

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Major Natural Language Processing Corpora

• PennTreebank (1993) 4.9 million words, tagged
  and parsed, not balanced (optional paper in
  course pack)
• TIPSTER corpus- AP Newswire and Wall Street
  Journal mainly used for Information Retrieval
• More variety by National Corpora and dependency
  treebanks

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National Corpora

• British National Corpus (BNC Corpus)
• 100 million words, 90 written, 10 spoken, BNC
  Baby 2 million word sampler, SARA and Xaira
  its own corpus query tools, wholly tagged by
  CLAWS tagger
• American National Corpus (ANC)
• In progress, preliminary releases available
• Czech National Corpus (optional paper in course
  pack)
• 12 full time persons working for 5 years in a
  speacialized institute
• 100 million words
• Partially tagged and parsed in Prague Dependency
  School tradition
• See METU Online links

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Lecture 2

• Corpus Design Issues
• Readings
• Tognini-Bonelli (2001) Corpus Issues. Ch3
• McEnery et al(2006) Unit A7-A9, B1 all appear to
  be one article in the course pack
• Meyer (2002) Planning the Construction of a
  corpus. Ch 2.