What computers can and cannot do for lexicography or Us precision, them recall

1. What computers can and cannot do for lexicographyorUs precision, them recall Adam Kilgarriff Lexicography Masterclass Ltd and University of Brighton, UK

2. Outline • Precision and recall • History of corpus lexicography • Natural Language Processing • Cyborgs Adam Kilgarriff: Us precision them recall

3. Find me all the fat cats • a request for information Adam Kilgarriff: Us precision them recall

4. High recall • Lots of responses • Maybe not all good Adam Kilgarriff: Us precision them recall

5. High precision • Fewer hits • Higher confidence Adam Kilgarriff: Us precision them recall

6. Us precision, them recall Adam Kilgarriff: Us precision them recall

7. Us precision, them recall • True in many areas • web searching, google • finding an image to illustrate a talk • Nowhere more so than lexicography Adam Kilgarriff: Us precision them recall

8. Lexicography: finding facts about words • collocations • grammatical patterns • idioms • synonyms • antonyms • meanings • translations Adam Kilgarriff: Us precision them recall

9. Outline • Precision and recall • History of corpus lexicography • Natural Language Processing • Cyborgs Adam Kilgarriff: Us precision them recall

10. Four ages of corpus lexicography Adam Kilgarriff: Us precision them recall

11. Age 1: • Pre • computer • Oxford English • Dictionary: • 5 million • index cards Adam Kilgarriff: Us precision them recall

12. Age 2: KWIC Concordances • From 1980 • Computerised • COBUILD project was innovator • asian-kwic.html • the coloured-pens method Adam Kilgarriff: Us precision them recall

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, slow • 5000 lines: no Adam Kilgarriff: Us precision them recall

14. Age 3: Collocation statistics • Problem:too much data - how to summarise? • Solution:list of words occurring in neighbourhood of headword, with frequencies • Sorted by salience Adam Kilgarriff: Us precision them recall

15. Collocation listing For right collocates of save (>5 hits) Adam Kilgarriff: Us precision them recall

16. Collocation statistics • Which words? • next word • last word • window, +1 to +5; window, -5 to -1 • How sorted? • most common collocates --but for most nouns it's the • most salient collocates --how to measure salience? Adam Kilgarriff: Us precision them recall

17. Mutual Information • Church and Hanks 1989 • How much more often does a word pair occur, than one might expect by chance • “Chance” of x and y occurring together: p(x) * p(y) • Probabilitiesapproximated by frequencies p(x) =(approx) f(x)/N Adam Kilgarriff: Us precision them recall

18. Mutual Information * numbers are log-proportional to MI Adam Kilgarriff: Us precision them recall

19. Problem • mathematical salience = lexicographic salience? • no! higher-frequency items are lexicographically more salient • Solution multiply MI by raw frequency Adam Kilgarriff: Us precision them recall

20. Mutual Information Adam Kilgarriff: Us precision them recall

21. Collocation listing For right collocates of save (>5 hits) Adam Kilgarriff: Us precision them recall

22. Age-3 collocation statistics: limitations Lists contain • junk • unsorted for type --MI lists mix adverbs, subjects, objects, prepositions What we really want: • noise-free lists • one list for each grammatical relation Adam Kilgarriff: Us precision them recall

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, as before Adam Kilgarriff: Us precision them recall

24. Can we do it? • high-accuracy parsing is hard • lots of NLP work, many parsing frameworks exist • if any parser can handle large corpus, it's probably good enough--- sorting, statistics, make us error-tolerant Adam Kilgarriff: Us precision them recall

25. Can we do it? • high-accuracy parsing is hard • lots of NLP work, many parsing frameworks exist • if any parser can handle large corpus, it's probably good enough--- sorting, statistics, make us error-tolerant • Poor man’s parsing: • object (of active verb) = last noun in any sequence of nouns, adjectives, determiners, numbers and adverbs following the verb Adam Kilgarriff: Us precision them recall

26. The word sketch • coffee_n.html Adam Kilgarriff: Us precision them recall

27. Macmillan Dictionary of English for Advanced Leaners, 2002: editor: Rundell. Work done 1999. • Word sketches produced for 6000 most common nouns, verbs, adjectives of English • using British National Corpus (100 M words, already POS-tagged) • lemmatized using John Carroll's lemmatizer • parsed using regular expressions over POS-tags • HTML files with hyperlinked corpus examples • lexicographers used them extensively, used instead of going direct to corpus • positive feedback Adam Kilgarriff: Us precision them recall

28. Outline • Precision and recall • History of corpus lexicography • Natural Language Processing • Cyborgs Adam Kilgarriff: Us precision them recall

29. Natural Language Processing • The academic discipline which provides the tools • Also known as Computational Linguistics, Human Language Technology (HLT), Language Engineering • Good at evaluation of its tools • Good news for lexicography: • identify the best tools, apply them to our corpora Adam Kilgarriff: Us precision them recall

30. An Anglophone Apology • Technology, tools, resources most often available for English • This talk centres on English • Other languages often present new problems • Finding word delimiters for Chinese is hard • Finding bunsetsu for Japanese is hard • Fewer resources available, less work done • Recommendation: • find the local experts for your language Adam Kilgarriff: Us precision them recall

31. Recap: Lexicography: finding facts about words • collocations • grammatical patterns • idioms • synonyms • antonyms • meanings • translations Adam Kilgarriff: Us precision them recall

32. Recap: Lexicography: finding facts about words • collocations - sketches • grammatical patterns - sketches • idioms • synonyms • antonyms • meanings • translations Adam Kilgarriff: Us precision them recall

33. Idioms • Extreme case of collocation/multi word expressions • Sequence of workshops on collocations, MWE • Technical terms (of great interest to technologists, technical): TERMIGHT Adam Kilgarriff: Us precision them recall

34. Antonyms • Essential semantic relation Adam Kilgarriff: Us precision them recall

35. Antonyms • Essential semantic relation but • Justeson and Katz 1995: distributional evidence for typical antonym pairs • rich men and poor men • the big ones and the small ones • black and white issues • Perhaps antonyms are ‘really’ distributional Adam Kilgarriff: Us precision them recall

36. Thesauruses • Also near-synonyms • are there any true synonyms? • Distributional: which words share same distributions • if corpus contains object(drink, wine), object(drink, beer) • 1 pt similarity between wine and beer • gather all points; find nearest neighbours • Sparck Jones, Lin, Grefenstette Adam Kilgarriff: Us precision them recall

37. Nearest neighbours Adam Kilgarriff: Us precision them recall

38. Translation • Parallel corpora • Texts and their translations or • Comparable corpora • Matched for source and target (genre and subject matter), not translations • Which L1 words occur in equivalent L1 settings to L2 words in L2 settings? • They are candidate translation pairs • Very hard problem • Lots of high quality research Adam Kilgarriff: Us precision them recall

39. The WASPbench • with David Tugwell, supported by UK EPSRC, grant M54971 A lexicographer's workbench • runtime creation of word sketches • integration with Word Sense Disambiguation technology • output is "disambiguating dictionary" - analysis of word's meaning into senses, plus computer program for disambiguating contextualised instances of the word • First release now available. http://wasps.itri.brighton.ac.uk/ • Sketches at http://www.itri.brighton.ac.uk/~Adam.Kilgarriff/wordsketches.html Adam Kilgarriff: Us precision them recall

40. The Sketch Engine • Input: • any corpus, any language • Lemmatised, part-of-speech tagged • specification of grammatical relations • Word sketches integrated with • Corpus query system • Supports complex searching, sorting etc • First release early 2004 Adam Kilgarriff: Us precision them recall

41. Outline • Precision and recall • History of corpus lexicography • Natural Language Processing • Cyborgs Adam Kilgarriff: Us precision them recall

42. Cyborgs • Robots: will they take over? • Rod Brooks’s answer: • Wrong question: greatest advances are in what the human+computer ensemble can do Adam Kilgarriff: Us precision them recall

43. Cyborgs • A creature that is partly human and partly machine • Macmillan English Dictionary Adam Kilgarriff: Us precision them recall

44. Adam Kilgarriff: Us precision them recall

45. Adam Kilgarriff: Us precision them recall

46. Adam Kilgarriff: Us precision them recall

47. Adam Kilgarriff: Us precision them recall

48. Cyborgs and the Information Society The dictionary-making agent is part human (for precision), part computer (for recall). Adam Kilgarriff: Us precision them recall

49. Treat your computer with respect. You and it can do great things together. Adam Kilgarriff: Us precision them recall

50. Lexicographers of the future? Adam Kilgarriff: Us precision them recall