Computational Linguistics: Computers and the Brain

University of MarylandYakov Kronrod

Dan ParkerIrene Eleta

Raul David GuerraJudith Klavans

Different StrokesComputers Human Brain

store representationscombine previously acquired information

retrieve past “knowledge”can “see”, “hear”, “speak”?

digitalprocess specific instruction

programmableinfallible (as far as programming

goes)fast complex computations

very bad at reasoninglargely serial processing

organiccan modify behavior on the fly

can learn wellprone to mistakes

slow at complex computationsvery good at reasoning

largely parallel processing

What’s the connection?

• What do computers have to do with Language?

• Holy Grain: Full Language Understanding• NLP vs. CL

Types of Computational Linguistics and Natural Language Processing

• Speech Recognition/Comprehension• Speech Production• Language Induction• Lexical Analysis• Semantic Analysis• Machine Translation• Language Modeling• Cognitive Processing Modeling

Computational Linguistics: Defined• Computational linguistics is an interdisciplinary field

dealing with the statistical and/or rule-based modeling of natural language from a computational perspective. Computational linguists often work as members of interdisciplinary teams, including linguists (specifically trained in linguistics), language experts (persons with some level of ability in the languages relevant to a given project), and computer scientists. In general, computational linguistics draws upon the involvement of linguists, computer scientists, experts in artificial intelligence, mathematicians, logicians, philosophers, cognitive scientists, cognitive psychologists, psycholinguists, anthropologists and neuroscientists, among others.

Computational Linguistics: Defined• Natural language processing (NLP) is a field of

computer science and linguistics concerned with the interactions between computers and human (natural) languages. In theory, natural-language processing is a very attractive method of human-computer interaction. NLP has significant overlap with the field of computational linguistics, and is often considered a sub-field of artificial intelligence. Research into modern statistical NLP algorithms requires an understanding of a number of disparate fields, including linguistics, computer science, and statistics.

Building Blocks: Words

• Commonly seen as the basic building block of language(Letters? Sounds? Noises?)

• Can express basic thoughts(ie: give, please, that, etc…)

• Used to construct sentences• Used to convey associations and emotions• Placeholders for concepts and images

Words in the Brain

• “Tip of the tongue” phenomena• So many to keep track of• How do we remember a word we want?• Needed to process a sentence

Digitizing the Word

• Words can be used as “tokens” to compute many different things

• Words can be used to keep track of associations and descriptions

• Search and Learning using words in computers

1 picture; 1000 words

But First…

…A few words from our resident Linguist.

Words in the Mind

Where are words stored?

The Mental

LEXICON

The Mental Lexicon:

• Holds all of the words you know.

• How many words are in our lexicon?

~60,000 words!

The lexicon is not just a bag of words…

But it’s also not a dictionary…

Because you know so many words, the brain needs to find words VERY quickly.

How might a word be accessed?

Cane

Cap

Cane

Candle

Dog

Cookie

How might a word be accessed?

Cap

Cane

Candle

Dog

Cookie

C___

How might a word be accessed?

Cap

Cane

Candle

Dog

Cookie

C___

How might a word be accessed?

C___

Cap

Cane

Candle

Dog

Cookie

How might a word be accessed?

CA__

Cap

Cane

Candle

Dog

Cookie

How might a word be accessed?

CA__

Cap

Cane

Candle

Dog

Cookie

How might a word be accessed?

CAN_

Cap

Cane

Candle

Dog

Cookie

How might a word be accessed?

CAN_

Cap

Cane

Candle

Dog

Cookie

How might a word be accessed?

CANE

Cap

Cane

Candle

Dog

Cookie

How might a word be accessed?

CANE

Cap

Cane

Candle

Dog

Cookie

Image from http://www.psych.nyu.edu/pylkkanen/Neural_Bases/07_slides/11_LexAccess_Elect.pdf

Celebrate

Party

birthday

joy

positive

negative

death

Cheer

Sorrow

remorse

Emotion:

Title: Portrait of a Family Playing Music

Title: The Studio

Title: Girl at the Piano: recording sound

Title: Portrait of a Family Playing Music

cello violin

musicians

music

abstractcolorful

piano

geometric

music

An image is worth a thousand words……in all languages

(or how people from different cultures build the many meanings of an image)

Two women

Sewing

Light and shadow

Doves

Crown of thorns

Melancholy

La Virgen

Cosiendo

Cristo

Corona de espinas

Luz y sombra

tranquilidad

US Spain

Cotton pickingtwo girlsAfrican Americanslavery

RacismSouthernThe SouthCivil war

Museum User Museum Expert

Boat Builders, set on the Gloucester, Massachusetts coast relates to a series of prints and drawings devoted to shipbuilding. Homer also used this image of the two boys in an engraving for the October 11, 1873 issue of Harper’s Weekly. ………..

I remember a boat …

<vessel, boat, lake, marine,

ocean, sails, schooner,

ship ,water>

<vessel,china,handle,dynasty,j

ade,stone>

<vessel,boat,ocean,overcast,

paddle,river,sail,ship,water,

vastness >

Looking Forward

• Advances in Bridging the Linguistics – NLP gap• Directions of research for language processing• Better models for human language usage• Cross-pollination of ideas across disciplines

Thank You!

• Questions• Comments• Discussion