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language acquisitionkyle e. chambers

2007.11.13

the mystery

?at birth by age 4

milestones

• 0-1 month: cooing• 6 mos: babbling• 12 mos: first word• 12-18 mos: one word speech• 18-24 mos: two word speech• 2-4 years: more complex structures• 4-5 years: done

you’re not born with it

you don’t memorize it you learn the rules

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induction problem

• 1, 3, 5,…

• many solutions consistent with the databut inconsistent with each other

what could help?

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filter

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bias

in the womb filtered input

• language rhythm• speech from non speech• mother’s voice from other voices

language discrimination video language discrimination

• high-amplitude sucking (HAS) procedure

• newborns discriminate native fromnonnative language

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prenatal memory for speech(Kisilevsky et al., 2003)

2 min silence 2 min silencemom’s voice

female stranger2 min silence 2 min silence

• Fetal heart rate increased in response tomother’s voice only

mommy dearest

• Infants prefer mom’s voice to astranger’s

• They seem to have memory for mom’svoice…

constraints and biases

• the input infants receive influences whataspects of language they learn first

case study of word learning

milestones

• 0-1 month: cooing• 6 mos: babbling• 12 mos: first word• 12-18 mos: one word speech• 18-24 mos: two word speech• 2-4 years: more complex structures• 4-5 years: done

facts about word learning

• 18 months: 50 words• 6 years: 9,000-14,000 words• 8 years: ~28,000 words• 9 new words per day--gadzooks!

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“cat”

“lookatthedoohickey”

learning a wordparts of word learning problem

• word form• word meaning

“lookatthedoohickey”

word form

• Remember characteristics of speech– Mom’s voice, stories read before birth

• Distinguish different speech sounds• Remember groups of sounds• Segment groups of sounds as potential

‘words’

• Nonnative contrasts– Hindi /da/~/da/

– Salish /q’a/~/k’a/

• For adults some nonnative contrasts are difficultto discriminate

• But you can’t be hardwired for your particularlanguage…

speech sound discrimination

phonetic discrimination video

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infant phonetic discrimination

• Conditioned headturn procedure• Conditioned to turn their head for an

obvious change– ma, ma, ma, ma,…ga

• Tested on nonnative contrasts– q’a, q’a, q’a, q’a,…k’a

00.10.20.30.40.50.60.70.80.9

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6-8months

Hindi contrastSalish contrast

Pro

port

ion t

hat

dis

crim

inate

Werker & Tees (1984)

8-10months

10-12months

Native 12 mos.

English learning infants Hindi & Salish learning infants

summary

• At birth infants can discriminate mostnonnative phonemic contrasts

• During the first year of life, infantsdiscrimination becomes languagespecific

exposure matters

Mandarin story telling Mandarin contrasts

yes

no

yes

noEnglish infants(10 months)

word form

• Remember characteristics of speech– Mom’s voice, stories read before birth

• Distinguish different speech sounds– Ability to discriminate nonnative contrasts

• Remember groups of sounds• Segment groups of sounds as potential

‘words’

words in isolation video

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remembering isolated words(Jusczyk & Aslin, 1995)

Isolated Words (dog & cup)Familiarization:

Test:Passages (dog & cup) Passages (feet & bike)The cup was bright and shiny.A clown drank from the red cup.The other one picked up the big cup.His cup was filled with milk.Meg put her cup back on the table.Some milk from your cup spilled on the rug.

>

results and discussion

• 7.5-month-old infants listened longer topassages that contained words they previousheard in isolation.

• They remember sequences of sounds

• Infants can detect familiar words in fluentspeech.

word form

• Remember characteristics of speech– Mom’s voice, stories read before birth

• Distinguish different speech sounds– Ability to discriminate nonnative contrasts

• Remember groups of sounds– Noticing words in passages (cup, bike)

• Segment groups of sounds as potential‘words’

word segmentation

word segmentation cues for word segmentation

• Words in isolation• Stress• Syllable co-occurrence

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words in isolation

coffee

idrinkmycoffeeblack

words in isolation

• If using words in isolation is going towork, what needs to be true?

• Do parents use words in isolation?– When mothers taught their child a new word– Many never produced the word in isolation

cues for word segmentation

• Words in isolation• Stress• Syllable co-occurrence

stress

• Sw or wS• record vs. record• Sw predominant pattern of English

– daddy, mommy, table…

• Can stress be used to segment words?

segmenting with stress(Jusczyk, Houston, & Newsome, 1999)

Your kingdom is in a faraway place. The prince used to sail to that kingdom.... One day he saw a ghost in this old kingdom. The kingdom started to worry him. So he went to another kingdom. Now in the big kingdom he is happy.

Isolated Word (kingdom)

Familiarization:

Test:

Passages (kingdom)

> Isolated Word (candle)

segmenting with stress(Jusczyk, Houston, & Newsome, 1999)

The man put away his old guitar.

Your guitar is in the studio. That red guitar is brand new. The pink guitar is mine. Give the girl the plain guitar. Her guitar is too fancy.

Isolated Word (guitar)

Familiarization:

Test:

Passages (guitar)

= Isolated Word (candle)

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did they segment anything?(Jusczyk, Houston, & Newsome, 1999)

The man put away his old guitar.

Your guitar is in the studio. That red guitar is brand new. The pink guitar is mine. Give the girl the plain guitar. Her guitar is too fancy.

Isolated Word (taris)

Familiarization:

Test:

Passages (guitar)

> Isolated Word (candle)

conclusion

• So, 7.5-month-old English learninginfants segment a speech stream with aSw bias...

conundrum

• Experience with strong-weak wordshelps segment words from the speechstream

• Why can’t these be the only cues thatinfants use to segment words?

conundrum

• Experience with strong-weak wordshelps segment words from the speechstream

• Why can’t these be the only cues thatinfants use to segment words?

cues for word segmentation

• Words in isolation• Stress• Syllable co-occurrence

statistical learning in speech

• buyfairtradecoffee• ilikemyhomemadecoffee• acupofcoffeedoesthebodygood• coffeeisgoodinthemorning

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statistical learning in speech

• buyfairtradecoffee• ilikemyhomemadecoffee• acupofcoffeedoesthebodygood• coffeeisgoodinthemorning

“coffee”

• Syllables within a word are more likely tooccur together than syllables fromdifferent words.

– ty#ba (from pretty#baby) -- low probability– ba.by -- high probability

syllable co-occurrence(Harris, 1955; Saffran, Aslin, & Newport, 1996)

“pretty baby”“pretty flower”

“pretty girl”

co-occurrence demo

• Can we use statistical information tosegment words?– synthetic speech– no word boundaries– no prosody…

Which one sounds like thelanguage you just heard?

• 1. dapiku padoti

• 2. tupiro kugola

• 3. golabu tilado

• 4. titupi bidaku

speech stream

• golabutupiropadotibidakugolabubidaku– “go” is always followed by “la” and “la is

always followed by “bu”– “bu” can be followed by “tu”, “pa”, or “bi”

• words “golabu”• partwords “kugola”

Words, part words, nonwords

• 1. dapiku padoti

• 2. tupiro kugola

• 3. golabu tilado

• 4. titupi bidaku

non-words

part-words

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what about infants…

• 8-month-old infants

• Train:golabutupiropadotibidakugolabubidaku…– 2 minutes of concatenated speech

• Test: words (golabu) vs. part-words (kugola)

• Infants distinguished part-words (kugola) fromwords (golabu)

conclusions

• Infants can use syllable co-occurrence tosegment a continuous speech stream.

• Unlike stress, this doesn’t requireknowledge of ‘words’ before it works.

word form

• Remember characteristics of speech– Mom’s voice, stories read before birth

• Distinguish different speech sounds– Ability to discriminate nonnative contrasts

• Remember groups of sounds– Noticing words in passages (cup, bike)

• Segment groups of sounds as potential‘words’– Syllable co-occurrence leads to ‘words’

to be continued….