Ling 240: Language and Ling 240: Language and MindMind

Acquisition of PhonologyAcquisition of Phonology

English

[p[phh]]

[b][b][p][p]

Hindi

[p][p][p[phh]]

[b][b]

EnglishEnglish Japanese Japanese

[l][l]

[r][r]

[l][l]

[r][r]

Voice onset timeVoice onset time

VOT = the time between the release VOT = the time between the release of a stop and the voicing of a of a stop and the voicing of a following vowelfollowing vowel

Voice Onset Time (VOT)

60 msec

Discrimination

0ms

20ms

40ms

20ms

40ms

60ms

D T

D

T T

D

Categorization of speech Categorization of speech soundssounds

We group sounds into categories, We group sounds into categories, despite physical variabilitydespite physical variability

Some physical differences are mentally Some physical differences are mentally represented as “not different”; others represented as “not different”; others as “different”as “different”

Is categorical perception innate?Is categorical perception innate?

How are mental categories acquired?How are mental categories acquired?

High Amplitude Sucking

Procedure• Initially sucking

rate increases (novelty)

• Then decreases• Decline in

response = habituation

LSCP Infant Lab

High Amplitude Sucking

Procedure

When sucking rate declines to a set point (habituation criterion),auditory stimulus is changed

LSCP Infant Lab

High Amplitude Sucking

ProcedureIf sucking rate increases,

then we know the infant has detected the change

• The renewed response = dishabituation

LSCP Infant Lab

Newborns are universal listeners

Infants perceive speech categorically

Newborns are sensitive to almost every phonological distinction yet tested

Newborns are universal listeners

In contrast, adults have difficulty discriminating speech sounds that are not contrastive in their native language

Hindi contrastsHindi contrasts

[dããt][dããt] toothtooth [DããT][DããT] scold, be angry withscold, be angry with

[taal][taal] ‘musical note’‘musical note’ [Taal][Taal] ‘to ignore’‘to ignore’

Newborns are universal listeners

English infants can distinguish Hindi /d/ and /D/

Japanese infants can distinguish between /l/ and /r/

Studies by Werker et alStudies by Werker et al

Infants are universal listeners but adults can’t discriminate non-native phonemic contrasts

Then there must be a decline across age

Questions: Questions: what is the role of experience?what is the role of experience? when exactly does this decline happen?when exactly does this decline happen? is this decline a critical period effect?is this decline a critical period effect?

Testing Across the Lifespan

• young infants

• older infants

• children and adults

Conditioned Head Turn Paradigm

Habituation (High Amplitude Sucking)

Just ask them: “Same or different?”

Visual Reinforcer (VR)

Toy that lights up and moves at the experimenter’s command

Controls for sound stimuli and the VR

Conditioned Head Turn• Child hears Stimulus 1 (/ba/)

repeatedly• Then Stimulus 2 is presented

(/da/)• If child detects difference, he

should turn to look at the visual reinforcer when the stimulus changes

• If child does not detect it, he shouldn’t turn

Conditioned Head Turn Paradigm

Kuhl Lab, U Washington, 1992

Werker 1995

Testing /ba/ vs. /da//Ta/ vs. /ta//tha/ vs. /dha/

Subjects: Hindi adultsEnglish AdultsEnglish 6-8 month-

olds

Werker 1995

/ba/ vs. /da/ Hindi and English

/Ta/ vs. /ta/ Only Hindi

/tha/ vs. /dha/ Only Hindi

Results

Werker, 1995

QuestionsQuestions

When does decline in When does decline in performance take place?performance take place?

What exactly is responsible What exactly is responsible for the decline?for the decline?

Does Does Critical PeriodCritical Period play a play a role?role?

General Methodology General Methodology questionquestion

We observe that infants behave one We observe that infants behave one way and adults behave another way.way and adults behave another way.

Goal: Goal: We want to know what changes We want to know what changes at what point in time.at what point in time.

What are some ways of obtaining What are some ways of obtaining this data?this data?

Werker & Tees 1984

Test infants of different ages (Cross-sectional)Test infants of different ages (Cross-sectional) Test the same group of infants at different Test the same group of infants at different

points in time (Longitudinal)points in time (Longitudinal)• 6-8 months6-8 months• 8-10 months8-10 months• 10-12 month10-12 month

Werker & Tees 1984: Werker & Tees 1984: NthlakampxNthlakampx

Native American language spoken by Native American language spoken by about 200 speakers (in 1984) in about 200 speakers (in 1984) in British Columbia—also known as British Columbia—also known as Thompson or SalishThompson or Salish

Nthlakampx Nthlakampx glottalized velarglottalized velar vs vs glottalized uvularglottalized uvular ejectives ejectives

[‘ki][‘ki] vs vs [‘qi][‘qi] Velar Velar ‘k..‘k.. Uvular Uvular ‘q…‘q…

Results

Werker & Tees, 1984

Werker studies: Conclusion

Ability to perceive non-native contrasts declines in 1st year

Werker and Tees 1984

What is responsible for the change?

How do babies become adults?

First proposal: First proposal: Maintenance/Loss Maintenance/Loss

HypothesisHypothesis role of experience is to role of experience is to

maintain perceptual maintain perceptual sensitivitiessensitivities

lack of exposure leads to loss lack of exposure leads to loss of perceptual abilityof perceptual ability

Maintenance/Loss Model

Ability

Time

Experience

1 year

No experience

ProblemsProblems for the for the Maintenance/Loss Maintenance/Loss

HypothesisHypothesis

Prediction?Prediction?

Decline in sensitivity following lack of exposure should bepermanent and absolute

Problems for the Problems for the Maintenance/Loss Maintenance/Loss

HypothesisHypothesisPredictions are not borne out: (1)Predictions are not borne out: (1)

Adults CAN perceive non-native Adults CAN perceive non-native contrasts contrasts

in (perceived) non-speech tasksin (perceived) non-speech tasks Zulu clicksZulu clicks

The link to listen to Zulu clicksThe link to listen to Zulu clickshttp://www.youtube.com/watch?v=gytCi5a7AJg

sounds in isolation (not syllables)sounds in isolation (not syllables)

Problems for the Problems for the Maintenance/Loss Maintenance/Loss

HypothesisHypothesis

Predictions are not borne out: (2)Predictions are not borne out: (2) Children older than 12 months Children older than 12 months

can move to a new country can move to a new country and acquire native phonologyand acquire native phonology

Alternative Hypothesis: Alternative Hypothesis: Functional ReorganizationFunctional Reorganization

no absolute hardware changes no absolute hardware changes in auditory systemin auditory system

development of a linguistic development of a linguistic system that imports a subset system that imports a subset of the contrasts from the of the contrasts from the auditory systemauditory system

ConclusionsConclusions

So, So, what changes during the first year?what changes during the first year? Answer:

the baby starts to acquire a linguistic system

As babies acquire a linguistic system As babies acquire a linguistic system (words) in their first year, they (words) in their first year, they “learn” which distinctions need to be “learn” which distinctions need to be represented represented in that systemin that system