Language Development

high amplitude sucking procedure time

birth to 4 months of age

high amplitude sucking procedure

- relies on infants sucking reflex

- infants hear sound stimulus every time they produce strong/high- amplitude suck on pacifier

- number of strong sucks indicator of infant’s interest

preference high amplitude sucking procedure

- used to test infants’ preference for different stimuli

preference = infants suck more during one stimulus

preference high amplitude sucking procedure method

- 2 different stimuli played on alternating minutes each time strong suck produced

- number of strong sucks produced during presentation of each stimuli is compared

discrimination high amplitude sucking procedure

used to test whether infant can tell difference between two auditory stimuli

variation of visual habituation paradigm

habituation phase of high amplitude sucking procedure

each time infant produces strong suck, sound played

> continues until sucking has declined significantly

test phase of high amplitude sucking procedure

hear new speech stimuli every time produces strong suck

- if distinguish between stimuli, sucking should increase

speech perception in infancy

- using high amplitude sucking paradigms, research has shown that newborns:

> prefer to listen to speech sounds over artificial sounds

> prefer mother’s voice over another woman’s voice

> prefer to listen to native language vs. other language

speech perception in infancy implication

language learning starts in utero

voice onset time (VOT)

length of time between when air passes through lips and when vocal cords start to vibrate

categorical perception

perceive speech sounds as distinct categories even though differences between speech sounds is gradual

Classic study by Elias

infant categorical perception of speech

Classic study by Elias method

> tested 1 month old infants learning English

> high amplitude sucking paradigm to test discrimination between /ba/ and /pa/

2 groups of classic study by Elias

- different speech sounds: infants habituated to /b/ (20ms VOT) and tested with /pa/ (40 ms VOT)

- same speech sounds: infants habituated to 60 ms VOT /pa/ and then tested with 80 ms VOT /pa/

Classic study by Elias result

Same speech sounds:

no change sucking when sound from category /pa

Different speech sounds:

increased sucking when sound from new category /pa/

> newborns have same categorical perception of speech as adults

infant cross-language speech perception

- infants make more distinctions between speech sounds than adults

- adults have difficulty perceiving differences between speech sounds that are not important in their native language

Classic study by Werker

infant cross-language speech perception

Classic study by Werker method

> tested 6 month olds American Infants Learning English

> high amplitude sucking paradigm to see if they can discriminate between Hindi /Ta/ and /ta/

Classic study by Werker results

after habituating to one of these Hindi speech sounds, increased sucking when hearing other speech sounds

Classic Study by Werker implications

> infants discriminate between speech sounds they have never heard before

> infants biologically ready to learn any of world’s languages

word segmentation

discovering where words begin and end in fluent speech

beings around 7 months of age

how to find words in speech

- pick-up on patterns of native language via statistical learning

> stress-patterning

> distribution of speech sounds

stress patterning

different languages place stress on different parts of word

> English: stress usually on first syllable

> French: stress usually on last syllable

distribution of speech sounds

- sounds that appear together often likely to be words

- sounds that don’t appear together often more likely to be boundaries between words

preferential listening procedure method

- speaker on either side of infant’s head

- when looking at speaker, recording of speech plays

> different speech from each speaker

preferential listening procedure

how long infant spends looking in particular direction/listening to particular sound indicates how much they like it

• familiarity effect

• novelty effect

familiarity effect

will listen longer to sounds they recognize

novelty effect

if first habituated to sound, will listen longer to new word

distribution of speech sounds method

preferential listening procedure

distribution of speech sounds habituation

8 month old listen to stream of syllables for long time

- some syllables always occurred together

- others rarely or never occurred together

distribution of speech sounds test

presented with syllable sequence that always co-occurred (tokibu) vs. syllable sequences that rarely co-occurred together (bagopi)

distribution of speech sounds results

listened longer to rarely occurring sequence

> shows that infants understood word boundaries by detecting

likelihood of syllables belong together

cooing

- start around 2 months of age

- drawn out vowel sounds, like ooooohhhhh, aaahhhhhh’

- helps infants gain motor control over vocalizaitons

- elicits reactions from caregivers leading to back and forth cooing with caregivers

babbling

- starts around 7 months of age (6-10 months)

- repetitive consonant vowel syllables, like papapapa

> speech sounds not necessarily from native language

> infant babbling similar across langauge

babbling and deafness

Deaf infants exposed to ASL babble with repetitive hand movements made up of pieces of full ASL signs

> evidence that language exposure critical for babbling

babbling functions

social function

learning function

learning function

signal that infant is listening and ready to learn

- infant learn more when adult labels new object just after they bubble vs. learning word in absence of babbling

social function

practicing turn-taking in dialogue

- infant babbling elicits caregiver reactions which in turn elicits more babbling

understanding words before first words

infants appear to understand high frequency words around 6 months of age

understanding words before first words study

show infants pictures of common items and monitor where they look when on picture is named

understanding words before first words result

6 month olds look to correct picture more often than chance

> shows that infants understand more words they can produce and understand more words than caregivers realize

first words

around 12 months of age (10-15 months)

- any specific utterance consistently used to refer to or express meaning

can be tricky to identify

often mispronounced in predictable ways

- usually refer to family members, pets, or important objects

- meaning of first words very similar across cultures

> suggests ash infants around world have smilier interest and priorities

tricky to pronounce first words

> babbling can sound like words

> meaning of first word can differ from its standard meaning

mispronouncing first words

> omit difficult parts of words

> substitute difficult sounds for easier sounds

> re-order sounds to put easy sound first

limitations of first words

- infants express themselves initially with only one word utterances so cannot clearly communicate what they want to say

• overextension

• under extension

overextension

using word in broader context than is appropriate

ex: dog refers to any 4 legged animal

under extension

using word in more limited context than appropriate

ex: cat only refers to family’s pet cat

learning more words

- 18 months of age

> knows about 50 words

> vocabulary spurt: rate of word learning accelerates

how do children learn words

- children’s assumptions about language

- social contex

> caregivers

> peers

children’s assumptions in word learning

> mutual exclusivity

> whole-object assumption

> pragmatic cues

> adult’s intentionality

> grammatical form

> shape bias

> cross-situational word learning

mutual exclusivity assumption

- given object/being will only have one name

> child will turn attention to object they don’t have a name for when they hear new word

> bilingual children follow this rule less

whole-object assumption

word will refer to whole object rather than part or action of object

pragmatic cues

- using social context to infer meaning of word

- adult gaze

adult gaze

when adult says new word, child assumes that it refers to object the adult is looking at even if child cannot see it

adult’s intentionality

if adult uses word that conflicts with child’s word for that object, they will learn new word if it is said with confidence

grammatical form

- grammatical form of word influences whether it is interpreted as noun, verb, or adjective

shape bias

children will apply noun to a new object of same shape, even if that object is very different in size, color, or texture

cross situational word learning

- determined word meanings by tracking correlations between labels and meanings across contexts

caregivers influence on word learning

children’s vocabularies hugely impacted by vocabularies and speech of caregivers

> infant directed speech

> quantity of pseech

> quality of speech

infant directed speech (IDS)

- distinctive mode of speech when talking to babies and toddlers

- common in majority of cultures around world

characteristics of IDS

> greater pitch variability

> slower speech

> shorter utterances

> clearer pronunciation of vowels

> more word repetitions

> more questions

> accompanied by exaggerated facial expressions

functions of IDS

> draw infants’ attention to speech

- infants prefer IDS to regular adult speech

> because infants pay greater attention to IDS, facilitates language learning

IDS and early word recognition study

> 7-8 month old infants introduced to new words either in:

- IDS

- regular adult speech

> recognition of words tested 24 hours later with preferential listening procedure

- all speech in recognition testing presented in IDS

IDS and early word recognition result

> infants looked longer at words introduced in IDS than adult speech

> inducts IDS facilitates recognition of words

quantity of speech

- number of words children hear used around them predicts children’s vocabulary size

> especially speech directed to child

- children that hear more words have larger vocabularies

Quantity of speech and SES study

parent’s SES predicts how much speech infant hear

Quantity of speech and SES method

tested parents with their 7 month old children over 2.5 years until child turned 3 years of age

> high, middle, and low SES

> came to lab an hour every week

> everything parent and child said was recorded and analyzed

implications of effect of SES

- children from high SES have larger vocabularies than kids from low SES

- differences in language exposure contribute to achievement gap between higher and lower SES children 

quality of speech

- richness of adult communication with children predicts children language ability

> joint engagement

> fluency

> stressing and repeating new words

> playing naming games

> naming object when toddler already looking at it

grocery store intervention

> focuses on increasing amount of time parents spend talking to children

> signs placed in grocery stores in low SES neighborhoods encouraged parents to talk to their children about foods in store

> parents increases quantity and quality of speech to their child

peers’ influence on language

placing preschool children with similarly poor language ability in the same classroom negatively impacts their language cgrwoth

- better chance to “catch-up” on language ability if:

> placed with children with higher language ability

> teachers use rich communication with students

first sentences

2 years of age

telegraphic speech

telegraphic speech

2-3 words phrases that leave out non-essential words

Learning grammar

- Age 5: mastered basics of grammar

> allows children to express and understand more complex ideas

- know that children have learned the grammar of their language when they can apply grammatical rule to new word/context

over regularization errors

- speech errors in which children treat irregular forms of words as if they are regular

- evidence that they have learned grammatical rules but not exceptions to the rules

how is grammar learned

- parents and other caregivers:

> model grammatically correct speech but generally don’t correct children’s grammatical erros

- statistical learning

how is grammar learned study

can infants pick up on new grammatical patterns?

> preferential listening paradigm

how is grammar learned habituated

to a list of 3 word sequences in which second word is repeated (ABB structure)

how is grammar learned test

presented with new sentences with same structure or with different structure (ABA)

how is grammar learned results

> 8 month olds look longer in direction of sentences with different structure

> evidence that infants can pick up on grammatical patterns

sentence to conversation 1-4 years

children initially struggle to engage in mutual conversation

> private speech

- infants’ speech often initially directed to themselves to organize action

sentence to conversation 5 years

able to stick to same conversation topic as their conversation partner

sensitive period of language acquisition

- period form birth to before puberty

> due to maturational changes in brain whereby language brain area become less plastic

- crucial period in which individual can acquire first language if exposed to adequate linguistic stimuli

> languages learned relatively easily during this period and full native competence is possible

- after the period, languages learned with great difficulty and native-like competence is rare

language acquisition evidence

• genie

• recovery after brain damage

• deaf individuals

• second language learners

genie

- from 18 years old until she was rescued at age 13, deprived of linguistic input

- could barely speak

> development also stunted in other areas

- language ability never fully developed despite intensive training after age 13

- evidence of sensitive period of language acquistion

> could also be due to inhumane treatment instead of linguistic deprivation

recovery after brain damage

children that sustain brain damage to language ares usually recover full language capability→ highly plastic

teenagers and adults that sustain brain damage to language areas are more likely to suffer permanent language impairment

> more mature brain is less plastic

deaf individuals study

researchers tested 2 groups of deaf adults:

> no exposure to language during early childhood

> learned spoken language during early childhood

- both groups began learning ASL in school between ages 9-15

- results: those with exposure to spoken language in infancy, even though spoken, performed better on language tasks than those with no language exposure

deaf individual follow up study

tested deaf adults that had exposure to ASL in early childhood

- performance of deaf adults with early exposure to ASL was same as  deaf adults with exposure to spoken language

-shows that exposure to language, regardless of modality, in infancy is critical for full language development

second language learners

- performance on English test by Chinese and Korean immigrants was related to age at which they first arrived in USA

- shows that language proficiency is related to first age of exposure to that language

> language performance is highly variable when language is learned after puberty

bilingual is norm

about 50% of people across the world use at least 2 languages on daily basis

monolingual brain hypothesis

belief that infants brains are programmed to be monolingual and that they treat input in 2 languages as if it were one language

monolingual brain hypothesis implication

if bilingual from birth, children will fondues their languages and could result in language delays

bilingualism in utero

bilingual learning begins in utero

bilingualism in utero study

> tested 2 groups of newborn infants

- bilingual English-tagalog mother

- monolingual English mothers

bilingualism in utero methods

preferential high amplitude sucking procedure

- exposed infants to tagalong English sentences

- measures rate of sucking on pacifier

- more intense sucking indicates preference for one language

bilingualism in utero results

> English monolinguals had preference for english

>english-tagalog bilinguals showed no consistent preference for either language

> suggest that bilingual infants start learning about 2 native languages pre-birth

bilingualism in utero differentiate

Can bilingual infants differentiate between 2 native langauges?

> bilingual english-tagalog mothers

> monolingual English mothers

bilingualism in utero differentiate methods

discrimination high amplitude sucking procedure

habituation: both groups habituated to enlighten or tagalong until sucking declined

test: hearing sentences in new language

bilingualism in utero results

> both bilingual babies and monolingual babies differentiated between taglog and English

> shows that bilingual infants can differentiate between native languages despite showing similar preference for both languages

two separate linguistic systems

- suggests that bilingual infants developing 2 separate language systems

> rather than confusing 2 languages

- goes against monolingual brain hypothesis