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Sketch Engine
A corpus query tool
Simon Smith & Adam Kilgarriff
Plan for these sessions
• Today
– lecture overview of SkE
• Homework
– Chinese collocation survey
– SkE walkthrough
• Next class
– Practical exercises
Plan for today
• Short review of corpus basics
• 4 ages of corpus research
– From pre-computer age, to SkE
• Functions of SkE
• Demonstration of SkE in use
Taiwan, Dec 2006
Sketch Engine
Developer: Pavel Rychly, Brno
Designer: Adam Kilgarriff
Users: OUP, Chambers, CUP
Universities for teaching and research
ELT textbook authors
Demo: http://www.sketchengine.co.uk/
• Self-registration for free account
Kilgarriff, Lexical ComputingSlide: 4
Quiz
• What’s a (linguistic) corpus?• What does the Latin word mean?• What are corpora?• What’s the BNC?• How big is the British National Corpus?• The BNC is
– Monolingual– Static– Synchronic– Balanced– English
• What other kinds are there?
5 major uses for linguistic corpora
• Language learning and teaching
• Theoretical research on Language and Linguistics
• Literary research and analysis
• Language technology
• Lexicography
• (=dictionary making)
– Cobuild, Longman, …
– All learner dictionaries now use corpora
How do you make a dictionary? (what resources…?)
• Use you own intuitions
• Ask all your friends for their intuitions
• Consult other dictionaries
• Read thousands of books
– and take lots of notes• Use a corpus
Taiwan, Dec 2006
Four ages of corpus
research (in lexicography)
Kilgarriff, Lexical ComputingSlide: 8
Pre-computer
KWIC concordance (KWIC=?)
Collocational tools
(what’s a collocation?)
Word Sketch (using Sketch Engine)
Taiwan, Dec 2006Kilgarriff, Lexical ComputingSlide: 9
Age 1:
Pre-computer
First Oxford
English (1860)
Dictionary:
• 20 million
index cards
– a word (usually
rare) and a citation
Taiwan, Dec 2006Kilgarriff, Lexical ComputingSlide: 10
Age 2: KWIC Concordance1 arity, which will be used to take a party of under-privileged children to D
2 from outside. You are invited to a party and after a couple of drinks you d
3 tion, we believe politicians of all parties will listen to our views. &equo
4 ould be reaching agreement with all parties concerned, as to which events,
5 lack people. I have certainly been party to one or two discussions amongst
6 . These should be discussed by both parties before entering into the relatio
7 presents They had hosted a cocktail party at Kensington palace, for example
8 akes. By midnight the end-of-course party is in full swing, but most cadet
9 e should be a right for the injured party to terminate the contract. A mana
10 by the Safran Peoples ' Liberation Party. This presents the powerful neigh
11 s. Ahead I could see the rest of my party plodding towards the final slope t
12 cial ethic. The two main political parties - the Tories and the Liberals -
13 ritish successes in Perth The small party of British players competing in th
14 to help control. One member of the party went to summon the rescue team and
15 rket society fashion magazine. The party was held at his flat which was a l
16 security and secrecy than any Tory Party Conference : it seems that bootleg
Taiwan, Dec 2006Kilgarriff, Lexical ComputingSlide: 11
Age 2: KWIC Concordances
From 1980
Computerised
COBUILD project was innovator
the coloured-pens method
Taiwan, Dec 2006Kilgarriff, Lexical ComputingSlide: 12
1 political association 4 person in an agreement/dispute
2 social event 5 to be party to something...
3 group of people
1 arity, which will be used to take a party of under-privileged children to D
2 from outside. You are invited to a party and after a couple of drinks you d
3 tion, we believe politicians of all parties will listen to our views. &equo
4 ould be reaching agreement with all parties concerned, as to which events,
5 lack people. I have certainly been party to one or two discussions amongst
6 . These should be discussed by both parties before entering into the relatio
7 presents They had hosted a cocktail party at Kensington palace, for example
8 akes. By midnight the end-of-course party is in full swing, but most cadet
9 e should be a right for the injured party to terminate the contract. A mana
10 by the Safran Peoples ' Liberation Party. This presents the powerful neigh
11 s. Ahead I could see the rest of my party plodding towards the final slope t
12 cial ethic. The two main political parties - the Tories and the Liberals -
13 ritish successes in Perth The small party of British players competing in th
14 to help control. One member of the party went to summon the rescue team and
15 rket society fashion magazine. The party was held at his flat which was a l
16 security and secrecy than any Tory Party Conference : it seems that bootleg
The coloured pens method
Taiwan, Dec 2006Kilgarriff, Lexical ComputingSlide: 13
Age 2: limitations
as corpora get bigger:
too much data
• 50 lines for a word: read all
• 500 lines: could read all, takes a long time
• 5000 lines: no
Why do corpora keep getting bigger? (anyone?)
• Because they can
– Price of storage
– Speed of access
• Representativeness
– Small corpus many examples of common words, maybe
– but…… ?
Lexical distribution
• What’s the most common word in English?
• What % does it make up of a whole corpus?
• The 100 most common words make up __% of all the words in a corpus?
• The 7500 most common words make up __%
• Answers:– 45% and 90%
• So: – you need massive corpora, if you want to really
represent rare words properly
19
Limitation of KWIC analysis
• As corpora get bigger: too much data
– 50 lines for a word: read all
– 500 lines: could read all, takes a long time
– 5000 lines: no
• Instead, create a statistical summary of
word usage
– Show most common collocates
Taiwan, Dec 2006
Age 3: Collocation listing, to find common
patterns (Problems here?)
word freq word freq
forests 6 life 36
$1.2 6 dollars 8
lives 37 costs 7
enormous 6 thousands 6
annually 7 face 9
jobs 20 estimated 6
money 64 your 7
Kilgarriff, Lexical ComputingSlide: 20
For right collocates of save (>5 hits)
21
Limitations of collocation listing
• Some items are not genuine collocates– yours appears only because it is adjacent to save
• The collocates can belong to any part of speech– It would better if they were classified into POS– and the role they play in the sentence
• Thus,– for arrest in “The police were quick to arrest a number of
suspects on the spot”
• We would like to see– Keyword: arrest– Subject: police– Object: suspect(s)– Modifier: on the spot
• We would not be especially interested in to, a and number– These non-collocates happen to be close to the keyword
Taiwan, Dec 2006Kilgarriff, Lexical ComputingSlide: 22
Age 4: The word sketch,
from Sketch Engine
A corpus-derived one-page summary of
a word’s grammatical and
collocational behaviour
Taiwan, Dec 2006Kilgarriff, Lexical ComputingSlide: 23
Age 4: The word sketch
Large well-balanced corpus
Parse to find
subjects, objects, heads, modifiers etc
One list for each grammatical relation
Statistics to sort each list
Taiwan, Dec 200624
Taiwan, Dec 200625
Functions of SkE
• KWIC concordance
– Sorting, filtering etc
• Word sketch
• Automatic thesaurus
• Sketch difference– discriminate near-synonyms
26
Corpora in language learning
• Teachers:– Use corpora to develop materials
– Confirm their own intuitions about L2
– Project info on screen, in-class
• Students can be set research tasks– Data-driven language learning (DDL)
– At home, or in computer classrooms
– Problem?
• Answer: pretty high motivation needed
28
Lexical approach to SLA
• What other “approaches” or “methodologies” are there?
• Brain stores linguistic knowledge– vocab (+features) and a lot of grammar rules– that’s basically what we have to learn
• Lewis (1993) and Schmitt (2000) say– the vocab is stored in chunks and collocations – kith is stored with kin– scotch is stored with rumour, and snake, and
whisky
• Saying strong car or powerful tea or broken house gives away non-native speakers
29
From www.teachingenglish.org - a lexical approach activity, based on a story text
More collocations?
• Let’s look them up
• Before next time–Sign up for Sketch Engine (you
should have already!)
–Take the pre-test, using your real name
–Do the walkthrough
–mcu.edu.tw/~ssmith/walkthrough