The Evolved ComputerComputation, Language, and

Computational Linguistics

Alex Hauptmann

School of Computer Science & Language Technologies Institute

Carnegie Mellon University

alex@cs.cmu.edu

Pop Quiz

When you meet someone new, you draw many conclusions about them. What is the strongest clue about their intelligence?

a) the gracefulness of their movements

b) the way they smell

c) how often they smile

d) how fast they do math problems

e) what they say and how they say it

Are Computers Intelligent?

• They can’t read books.• They can do arithmetic really fast.• They can’t answer questions too well.• They can look for relevant web pages.

– What about YouTube?

Computers are extremely good at following some kinds of rules.

Computer Science• What kinds of recipes are computers good at following?• What kinds of problems can be turned into “easy for

computers” recipes?– Intelligence?– Security and privacy?– Can computers work together on a recipe?

• How can we make it easy for people to write useful recipes?• How fast can computers follow a particular kind of recipe?• Is there a way to describe recipes mathematically?

As with most sciences,

there are theoretical and applied parts.

Two SecretsComputer science is no more about computers

than astronomy is about telescopes.

- E. Dijkstra, great computer scientist

Programming = the highly

useful craft of writing good recipes for a computer.

Computational LinguisticsWhich human language abilities are

easy-for-computers?

easy for computers

language tasks

What easy-for-computers language abilities are useful for humans?

hard/tedious for people to do

In the next three slides, you’ll see examples of some of the problems in CL.

Where are the words?

世界人权宣言联合国大会一九四八年十二月十日第 217A(III) 号决议通过并颁布1948 年 12 月 10 日， 联 合 国 大 会 通 过 并 颁 布 《 世 界 人 权 宣 言》。 这 一 具 有 历 史 意 义 的 《 宣 言 》 颁 布 后， 大 会 要 求 所 有 会 员 国 广 为 宣 传， 并 且“ 不 分 国 家 或 领 土 的 政 治 地 位 , 主 要 在 各 级 学 校 和 其 他 教 育 机 构 加 以 传 播、 展 示、 阅 读 和 阐 述。” 《 宣 言 》 全 文 如 下：

序 言OnDecember10,1948theGeneralAssemblyoftheUnitedNationsadoptedandproclaimedtheUniversalDeclarationofHumanRightsthefulltextofwhichappearsinthefollowingpages.FollowingthishistoricacttheAssemblycalleduponallMembercountriestopublicizethetextoftheDeclarationandtocauseittobedisseminated,displayed,readandexpoundedprincipallyinschoolsandothereducationalinstitutions,withoutdistinctionbasedonthepoliticalstatusofcountriesorterritories.

Where are the morphemes?İnsan hakları evrensel beyannamesiÖnsözİnsanlık ailesinin bütün üyelerinde bulunan haysiyetin ve bunların eşit ve devir kabul etmez haklarının tanınması hususunun, hürriyetin, adaletin ve dünya barışının temeli olmasına,İnsan haklarının tanınmaması ve hor görülmesinin insanlık vicdanını isyana sevkeden vahşiliklere sebep olmuş bulunmasına, dehşetten ve yoksulluktan kurtulmuş insanların, içinde söz ve inanma hürriyetlerine sahip olacakları bir dünyanın kurulması en yüksek amaçları oralak ilan edilmiş bulunmasına,On December 10, 1948 theGeneralAssembly of theUnitedNations adopted and proclaimed theUniversalDeclaration of HumanRights thefulltext of which appears in thefollowingpages. Following thishistoricact theAssembly called upon allMembercountries topublicize the text of theDeclaration and to cause it tobedisseminated, displayed, read and expounded principally in schools and other educationalinstitutions, without distinction based on thepoliticalstatus of countries or territories.

Which words are these?

(1) n dcmbr 10, 1948 th gnrl ssmbly f th ntd ntns dptd nd prclmd th nvrsl dclrtn f hmn rghts th fll txt f whch pprs n th fllwng pgs

اعُت�مد بموجب قرار الجمعية العامة (أ) كانون الأول 10) المؤرخ في 3 ألف (د-217

1948/ ديسمبر

Ambiguity in English

• IRAQI HEAD SEEKS ARMS• KIDS MAKE NUTRITIOUS SNACKS• BRITISH LEFT WAFFLES ON FALKLAND ISLANDS

• STOLEN PAINTING FOUND BY BUSH

Have you ever …

• Talked to a computer program on the phone?• Encountered a chat bot?• Used translation software for your Spanish

homework?• Taken an essay exam that was graded by a

computer?

How was that experience?

Handwriting PuzzleA student excuse for class, after bad automatic handwriting

recognition:

lie charm code soil rout wake he us this moving

my solemn circle did hot make I'll is taxis havingguy clam shute raid riot sale me ugh thai runningbye beam clock risk not wane be up tear morning

alarm visit must see loving

What kind of recipe for a computer could prevent this mistake?

Speech Recognition Puzzle

True example of computer speech recognition:“It is hard to wreck a nice beach”

• What was really said?

“It is hard to recognize speech”

What kind of recipe for a computer could prevent this mistake?

Ice cream <–> I scream

Technology: Can a computer program … Find relevant web pages? Transcribe speech? Check your spelling? Recommend books, CDs, movies?? Filter spam or classify email?? Answer trivia questions?? Translate the newspaper?? Summarize today’s news?? Watch a game and TV and know the score?? Scan a printed page into electronic text?? Read a story naturally, out loud?? Carry on an interesting conversation?? Tutor a student in a school subject?? Grade an essay or book report?

Science, Humanities, Society:

Can computers help us to …• Save a language from becoming extinct?• Help linguists study language more thoroughly and easily?• Build tools for literary or other scholars (e.g., concordances)• Study language evolution over time?• Make communication easier for the disabled?• Understand and model human cognition and learning?• Prevent terrorist attacks?• Increase communication and understanding across cultures• Predict natural disasters?• Find cures for diseases?*

*Surprising connection: many techniques from CL are now used in computational biology!

Phonebook ChallengeSome words in your dictionary also appear as last names in your phone book.For example, “brooks", “brown", “butler", “hall", and “wright" are in yourdictionary, and Brooks, Brown, Butler, Hall, and Wright are all common lastnames in the U.S.You would like to make a list of all such words. The inefficient way wouldbe to go through the dictionary in order: for each dictionary word, you openthe phone book, look up that word, add it to your list if you find it as a lastname, and close the phone book again.

(a) Why is it more efficient to keep the phone book open between word lookups?

(b) What if you have a friend to help you (and two copies of the dictionary and phone book)? How can the two of you divide up the work safely and finish twice as fast?

(c) What if there are three of you instead of two?

Computational Linguistics Olympiad

www.naclo.cs.cmu.edu • Challenge Puzzle Day

– 2/5/2007 @CMU McConomy Auditorium– and about 11 other places nationwide

• Final Challenge– 3/11/2007 also at CMU

• Training Camp/Summer Practice• International CL Olympics

– Late July in Bulgaria– National Team Competition – US Team won last year + best individual

• Was this just luck?

Thanks!

• Questions: alex@cs.cmu.edu