Psychology 110
Colorless green ideas sleep furiously
Noam Chomsky’s theory of Language
© Kip Smith, 2003
Language

Spoken, written, or gestured symbols
and

The way symbols are combined to
communicate meaning


Humans tend to use the symbols called words
But not all languages rely on words
© Kip Smith, 2003
How Symbols are Combined
Sentence
The boy hit the ball
The boy
Phrases
hit the ball
Words
The
th
boy
e
b
o
hit
i
h
i
Phonemes
© Kip Smith, 2003
the
t
th
ball
e
b
ä
l
The scientific method
Observations
Support
or
Refine
Hypotheses
© Kip Smith, 2003
Generate
Drive
Testing &
Experimentation
Language acquisition
Children are born with a propensity to
communicate and will learn a language
no matter what
© Kip Smith, 2003
Stages 1-3 of language acquisition

Birth


Babbling


“AH”
A rich variety of intonations
One concrete word

All refer to the here and now
© Kip Smith, 2003
Stages 4-6

Two words

Many different semantic relationships, e.g.



Telegraphic sentences

Function words (the, is, of) omitted


Agent - Action (“Doggie run”)
Attribute – Object (“Red ball”)
(“Doggie go bye-bye”)
Natural language

Gradual acquisition of vocabulary and
grammatical complexity
© Kip Smith, 2003
Overgeneralization

When learning the past tense of irregular
verbs

E.g., see saw, go went, sing sang, etc.

First, children use the irregular correctly

Then, they overgeneralize


seed, goed, singed
Then, they go back to the irregular
© Kip Smith, 2003
Evidence for ?

What does overgeneralization tell us about
language acquisition?





Examples
“I see her” but
“I seed her” instead of “I saw her”
“I go to sleep now” but
“I goed to sleep” instead of “I went to sleep”
© Kip Smith, 2003
Chomsky’s observations

Children learn language too fast for that learning
to be explained by learning alone


Children create novel sentences


Reinforcement and feedback are insufficient to account
for language learning
Not imitation
Everyone, even a child of seven, is capable of
generating more sentences than there are
seconds since the beginning of time
© Kip Smith, 2003
The scientific method
Observations
Support
or
Refine
Hypotheses
© Kip Smith, 2003
Generate
Drive
Testing &
Experimentation
Chomsky’s hypothesis:
Characteristics of all languages

Productivity


Language is structured in a way that enables
us to generate an infinite number of
meaningful utterances from a small set of
primitives (words)
Regularity


The utterances are systematic
There are acceptable and unacceptable
utterances
© Kip Smith, 2003
Productivity






It was night
It was a dark and stormy night
It was a dark and stormy Tuesday night
I’ll never forget that it was a dark and
stormy Tuesday night
My friend tells me that I’ll never forget that
it was a dark and stormy Tuesday night
This slide says that my friend tells me that
I’ll never forget that it was a dark and
stormy Tuesday night
© Kip Smith, 2003
The first principle of productivity

“The arbitrariness of sign”




F. deSaussure
The pairing of sound with meaning by
convention
“The word dog does not look like a dog, walk like a dog, or
woof like a dog, but it means dog just the same. It does so
because every English speaker has undergone an identical act of
rote learning in childhood that links the sound to the meaning.
“For the price of this standardized memorization, the
members of a language community receive an enormous benefit:
the ability to convey a concept from mind to mind virtually
instantaneously.” (Pinker, 1974, 75)
© Kip Smith, 2003
The arbitrary nature of meaning

Rock

Skirt

Grab

Grave

Brief

Letter

Boot

Boat
© Kip Smith, 2003
The 2nd principle of productivity

Semantics


The mapping between the symbols (words)
and what they stand for (their meaning)
The mapping is purely arbitrary & is
determined by convention within a linguistic
group
[also, the academic field that studies meaning]
© Kip Smith, 2003
Chomsky’s hypothesis:
Language is a discrete
combinatorial system

“Language makes infinite use of finite media”



Man bites dog  Dog bites man
We use a code to translate between orders of
words and combinations of thoughts
That code is called a Generative Grammar
© Kip Smith, 2003
Generative Grammar



The set of (implicit) rules that prescribe
the translation between word order and
thought
The set of rules that all children
unconsciously come to use to generate
acceptable utterances
The engine that drives makes a language
both productive and regular
© Kip Smith, 2003
On the structure of language

Grammar


A system of rules that provides the structure
to language
Syntax


The details of the grammar
Rules for combining words into grammatically
sensible sentences in a given language
© Kip Smith, 2003
Syntax structures

Word order
Phrase structure

Violations of syntax:







This is not a complete. This either.
This sentence no verb.
This sentence has contains two verbs.
This sentence has cabbage six words.
The child seems sleeping.
Drum vapor worker cigarette flick BOOM.
© Kip Smith, 2003
Chomsky’s theory (1959)


The acquisition and generation of
language CANNOT possibly be the product
of learning (classical and operant
conditioning)
There must be an innate capacity for
language

Knowledge of a “Universal Grammar”
© Kip Smith, 2003
Nature

+
Nurture
Evolution selects individuals
with the mechanisms for
understanding and producing
the structure of language
Chomsky:
The universal grammar
provides the templates
for understanding and
producing language

+
Experience relates sounds
(words) to what they stand
for (meaning, semantics)
Spoken language(s)
heard in the
environment
Mastery of your
native language
© Kip Smith, 2003
Chomsky’s theory


Language is fundamentally different than
all other behavior
The Universal Grammar is a discrete
combinatorial system
© Kip Smith, 2003
The components of language


A relatively small set of words (20,000)
and their mappings to meaning
A generative grammar, a kind of discrete
combinatorial system
© Kip Smith, 2003
The elements of the
generative grammar

Three types of rules
assure linguistic
regularity,




That is, they assure
the generation of an
acceptable utterance
Syntax
Semantics


Meaning
Phonology


© Kip Smith, 2003
Word order
Sound
Inflection
How language works

“The way language works, then, is that
each person’s brain contains a lexicon of
words and the concepts they stand for (a
mental dictionary) and a set of rules that
combine the words to convey relationships
among concepts (a mental grammar).”

(Pinker, 1994, 76)
© Kip Smith, 2003
One consequence of grammar’s
discrete combinatorial system

“If a speaker is interrupted at a random
point in a sentence, there are on average
about 10 different words that could be
inserted at that point to continue the
sentence in a grammatical and meaningful
way.”


(Pinker, 1994, 77)
In some places many more than 10, some
less
© Kip Smith, 2003
One consequence of grammar’s
discrete combinatorial system




Assume an average of 10 words per
insertion point, and
Assume most folks can produce
meaningful sentences 20 words long
How many different sentences is that?
At 5 seconds per sentence, how long
would it take to say them all?
© Kip Smith, 2003
Other discrete combinatorial systems

Grammar


DNA


4 bases
Numbers



Limited number of words
10 digits—Arabic numbers
7 letters—Roman numerals
Computer binary code

Strings of 0s and 1s
© Kip Smith, 2003
The scientific method
Observations
Support
or
Refine
Hypotheses
© Kip Smith, 2003
Generate
Drive
Testing &
Experimentation
One test of Chomsky’s theory

Colorless green ideas sleep furiously



Syntactically OK
Semantically irregular
Syntax and sense can be independent
© Kip Smith, 2003
More tests:
Phonology disambiguates

Read the following headline aloud



Hershey bars protest
Read it aloud again to generate a
completely different meaning
Again

Complaints about basketball team growing
ugly
© Kip Smith, 2003
Phonology

The sounds of language



Number varies across languages



Phonemes—smallest units of sound that can
change meaning
E.g., bat—that, /b/ and /th/ different
phonemes
English = roughly 40
Khoisan = 141
The sounds of language differ from other
sounds in the environment
© Kip Smith, 2003
Phonemic Invariance

A given phoneme is perceived the same
way in a variety of contexts



/t/ in “tip” vs. /t/ in “tube”
Sound spectrographs reveal that the 2 /t/
sounds are different in frequency
Different voices = different pitches

Still perceive words the same
© Kip Smith, 2003
X-Bar Theory
of Phrase Structure
Chomsky’s 1965
Aspects of a Theory of Syntax
© Kip Smith, 2003
Rule 1: Sentences


Example:

A sentence has two
parts:

Noun phrase (NP)

The happy girl
Verb phrase (VP)

Eats ice cream
&

The happy girl eats ice
cream
S
NP
© Kip Smith, 2003
The happy girl
VP
eats ice cream
Rule 2: Noun Phrases


Consists of an optional
determiner,
followed by any
number of adjectives,



The

Happy

Girl
[zero is a number]
followed by a noun
NP
© Kip Smith, 2003
det
A
N
the
happy
girl
Rule 3: Verb Phrases


Consists of a verb,
followed by a noun
phrase



Eats

Ice cream
Not required when verbs
are intransitive
E.g., flies, runs, eats
VP
© Kip Smith, 2003
V
NP
eats
ice cream
The power of a
phrase structure grammar

These three rules allow you to create
every declarative English sentence
S
NP
VP
det
A
N
V
NP
the
happy
girl
eats
ice cream
© Kip Smith, 2003
All you need to know
to speak basic English

3 simple rules





S
NP
VP
The mapping between
words and what they
mean

The generative phrase
structure grammar
A mental dictionary




© Kip Smith, 2003
Nouns
Verbs
Adjectives
Determiners
Modularity


The phrase structure
grammar allows nesting
Key words signal the
nesting


If S then S
Either S or S
VP
N
the
girl
© Kip Smith, 2003


the girl eats ice cream
then

the boy eats hot dogs
S
then
NP
det
If
S
S
If

V
NP
NP
det
eats ice cream the
VP
N
V
NP
boy
eats
hot dogs
Heads and Place Holders

The phrase structure
grammar holds words in
place


Either


or
A phrase inherits the
properties of its head

S
S
Either
VP
N
the
girl
© Kip Smith, 2003
gets candy
Who gets the candy?
S
or
NP
det

the girl eats ice cream
V
NP
NP
det
eats ice cream (the)
VP
N
V
NP
(girl)
gets
candy
Sub Phrases:

N
The phrase structure
grammar allows
subphrases to be
role-players

Prepositional phrases
N
N
student
PP
of linguistics
NP
© Kip Smith, 2003
det
A
the
happy
N
N
PP
student
of linguistics
Sub Phrases:

V
The phrase structure
grammar allows
subphrases to be
role-players
V
V
destroyed
NP
the hotel
room
S
NP
The WHO
© Kip Smith, 2003
V
V
destroyed
NP
the hotel
room
X-bar

X
“With this common design, there is no
need to write out a long list of rules to
capture what is inside a speaker’s head.
There may be just one pair of super-rules
for the entire language, where the
distinction among nouns, verbs,
prepositions, and adjectives are collapsed
and all four are specified with a variable
like “X.”

(Pinker, 1994, 103)
© Kip Smith, 2003
X



An X-bar consists of a head word,
followed by any number of role-players.
A phrase consists of an optional subject,
followed by an X-bar, followed by any
number of modifiers
This streamlined version of phrase
structure is called “the X-bar theory”
© Kip Smith, 2003
Categorical Perception

Voice Onset Time (VOT)


Time between when the sound is released at
the lips and when the vocal cords begin to
vibrate
[ba] vs. [pa]



/b/ is voiced, VOT for [ba] typically 0 ms
/p/ is not, VOT for [pa] typically around 40 ms
Categorical perception

Perceive discrete phonemic categories despite
gradual changes in VOT
© Kip Smith, 2003
Categorical Perception
© Kip Smith, 2003
Categorical Perception
Chance
Category
Boundary
© Kip Smith, 2003
Use it or Lose it

At birth, we are all able to recognize speech
sounds from any of the world’s languages
100
90
Percentage of 80
population 70
who are able
to discriminate
among the
various
Hindi T’s
60
50
40
30
20
10
0
© Kip Smith, 2003
Hindispeaking
adults
6-8
months
8-10
months
10-12
months
Infants from English-speaking homes
Englishspeaking
adults
Sadly

Learning a new language gets harder with
age
100
Percentage
correct on
grammar
test
90
80
70
60
50
Native 3-7
8-10 11-15 17-39
Age at first exposure
© Kip Smith, 2003
Why?

Critical Period Hypothesis (Lenneberg,
1969)



Children must be exposed to language within a
given period to learn it correctly
Set end of critical period at puberty
More supportive environment for children



Mistakes tolerated more
Adults don’t like to appear
Peers in similar situation
© Kip Smith, 2003
Why would language evolve?




To enable the transmission of knowledge
from one generation to the next?
To establish order in the social group?
To assess what others know?
To provide a means for revealing your
fitness and reproductive potential?



A peacock feather?
A fitness display?
An aid to courtship?
© Kip Smith, 2003
Colorless green ideas
sleep furiously
- Noam Chomsky
© Kip Smith, 2003
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Introduction to Psychology