LANGUAGE PROCESSING: HUMANS and COMPUTERS

PSYCHOLINGUISTICS

linguistic performance

Syntactic processingcomprehension speech

production

when we

speak

when we

listen

The Human Mind at Work

We access the lexicon and grammar to assign a

structure and meaning to the sounds we hear

We access our lexicon to find words

We use the rules of grammar to construct

sentences & to produce the sounds that expresses

the message

“ I quite agree with you, said the Duchess; “ and the moral of that is- ‘Be what you seem to be’ – or, if you’d like it more simply – ‘Never imagine yourself not to be otherwise than what it might appear to others….to be otherwise.’”“I think I should understand that better,” Alice said very politely, “if I had written down: but I can’t quite follow it as you say it.”

* A perfectly grammatical sentence and yet it is hard to understand.

Comprehension

Speech signal

can be described in physical or acoustic term.

Speech sound

Physically, a sound is produced when there is a disturbance in the position of air molecules.

Acoustic phonetics – is concerned only with speech sounds, all of which can be heard by the normal human ear.

Fundamental frequency

Spectrograms/ voiceprints

pitch

intensity

TERMINOLOGIESHow fast the variation of the air

pressure occur

Fundamental frequency of the sound when perceived

Loudness of the sound

Patterns of sounds

- difficulty of the listener to carve up the continuous speech signal into meaningful units.

- difficulty to distinguish two physically distinct instances of a sound are the same.

Speech Perception andComprehension

A sniggle blick is procking a slar.

Segmentation problem

Lack of invariance problem

Bottom-up and Top-down Models

the process by which we obtain information about themeaning and syntactic properties of a word from our mental

lexicon

The gypsy read the young man’s palm for palm for only a dollar.

Lexical access and word recognition

Semantic priming

syntactic and semantic relations among words and phrases in a sentence

The warehouse fires….. could continue in two ways: 1….were set by an arsonists 2….employees over sixty After the child visited the doctor prescribed a course of injections.

parsing

Syntactic processing

garden path sentences

• AnotAnother example of processing difficulty is a rewording of a Mother Goose poem.

Original form:

Rephrased

This is the dog that worried the cat that killed rat ate the malt that lay in the house that Jack built.

Jack built the house that the malt that the rat that the cat that the dog worried killed ate lay in.

Shadowing task

Average shadower can do with a delay of (500 ms)

Speech sound Subjects are asked to repeat what they hear as rapidly as possible

Exceptionally good shadowers can follow what is being said only a syllable behind (300 ms)

Technique to study sentence comprehension

starts with a speaker who produces an acoustic signal that represents a thought , idea, or message to be conveyed to the listener.

The hiring of minority faculty. The firing of minority faculty.

big and fat pig and vat

Speech error

Speech production

blends• produce part of one word and

part of another; selecting two or more words instead of deciding between them

1. splinters/ blisters splisters 2. edited/annotated editated 3. a swinging/ hip chick a swip chick

Lexical selection

Spontaneous errors show that the rules of morphology and syntax may also be applied when we speak.

1. groupment instead of grouping2. We swimmed in the pool.3. An burly bird instead of an early bird

Application and Misapplication of

Rules

nonlinguistic factors can be involved insometimes interfere with – linguistic processing. 1. He made hairlines He made headlines.

2. It can deliver a large payroll. It can deliver a large payload.

Nonlinguistic Influences

Computer Processing of Human Language

COMPUTATIONAL LINGUISTICS

Computational phonetics and phonology

Computational morphology Computational syntax

Computational sign language

Computational semantics

Computational pragmatics

• 20• process of analyzing the speech signal into it’s component phones and phonemes, and

producing in effect, a phonetic transcription of speech.

process of creating electronic signals that simulate the phones and prosodic features of

speech and assemble them into words and phrases for output to an electronic speaker.

Computational phonetics and phonology

Speech recognition

Speech synthesis

• \

converts written text into basic units of the synthesizer. It translates the input text into phonetic representation.

Text-to-speech

Difficulties: 1. The problem of words that spelled alike but

pronounce differently. e.g. She has read the book. She will read the book.

2. Inconsistent spelling e.g. I take it you already know Of tough and bough and cough and dough

Computational Morphology

The processing of word structures by computers.Programmed to look for roots and affixes. All words are placed into computer’s dictionary.e.g. walking - walk+ing fondness – fond+nesse.g. fax – faxes, fax’s, faxing, faxed, refax, faxable

Computational Syntax

Parser - is a computer program that attempts to replicate a grammar to assign in a phrase structure of words

Rules: S NP VP, NP Det Ne.g. The child found the kittens. top-down parser – child found the kittens bottom-up parser- The child found,the, kittens

the representation of the meaning of words and morphemes in the computer, as well as the meanings derived from their combinations.

• The computer tries to find concepts in its semantic representation capabilities that fit the words and structures of the input.

Computational Semantics

is the interaction of the “real world” with the language system.

e.g. He saw the boy with a bicycle. He saw the boy with a telescope.

Computational Pragmatics

• Linguists are working on computer algorithms that will recognize sign language much in the same way that speech may be recognized.

Purpose:1. To produce a dictionary of signs2. To enable a computer to search through ASL videos

for a particular sign, just as search engine like Google searches for certain key words in text documents.

Computational Sign Language

• computer models of grammar• Frequency analysis, concordances, and collocations• Computational lexicography• Information retrieval and summarization• Spell checkers• Machine translation• Computational forensic linguistics: trademarks interpreting legal termsspeaker identification

Application of Computational Linguistics