Language: Individual differences

Daniel Messinger, Ph.D.

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Language overview review

What is the normative course of infant language development? 

How do infant cries develop (directed and undirected)?

What are the stages of development of non-cry vocalizations?

What are some early milestones of verbal development (verbal development involves words)?

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Perspective

Last time– Features of language that all infants develop– Focus on production: speech

This time– How infants differ in learning language

Differences in learning to hear a first language Differences in learning to talk a first language Autism and deafness

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Today’s questions

How does the ability to distinguish between non-native speech sounds change in the first year?

– What does this mean about development?– Can distinctions between non-native sounds be taught?

How is language experience associated with later child language competence and IQ?

How is socioeconomic status associated with differences in language experience?

What does cochlear implantation teach us about language development?

Consider the spoken tokens of “doll.” To a Hindi speaker, the difference between the

“d” sounds in “this doll” versus “your doll”—a phonetic contrast between a dental [d8al] versus a retroflex [ɖal], respectively—would signal two possible word forms (either lentils or branch).

In English, both of those “d” sounds signal just one possible word form—phonetically labeled as an alveolar [dal].

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Different languages provide different phonetic experiences

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What’s going on?

English-learning infants hear Hindi contrast better than English-speaking adults

Almost as well as adult Hindi-speakers

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Dentral vs. retroflex "t"

Hindi AdultsInfantsEnglish Adults

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Distinguishing between non-native speech sounds in 1st year At birth, infants are capable of discriminating all

phonetically relevant differences in the world’s languages – They perceptually partition the acoustic space

underlying phonetic distinctions in a universal way. By 6 months of age, infants raised in different

linguistic environments show an effect of language experience.

Their representations are becoming language specific

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How does this develop?

Infants lose this ability in the first year of life, especially toward one year of age

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Dentral vs. retroflex "t"

6-8 Months8-10 Months10-12 Months

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What this mean for development

Very young infants can discriminate a wide range of phonetic contrasts in a variety of languages

Between 1 & 12 months, infants– increase knowledge of which syllables follow which in

their native language– but lose ability to make contrasts that do not occur in

their native language /r/ vs. /l/ . /b/ vs. /v/ . Te’ vs. te, tu’ vs. too

Development involves relatively permanent change, but not always improvement in all things.

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Parallels in speech production

Infant babbling shows little influence of native language.

Once the infant forms his/her 1st words than the sounds produced conform more closely to those of the native language

This corresponds to the stage at which infants begin to show language-specific sensitivity (10-12 months).

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Possible roles of experience

Induction – prior experience with a language is necessary because perceptual capability depends entirely on environmental input

Attunement – experience makes possible the full development of a capability.

Facilitation – experience effects only the rate of development of a capability.

Maintenance/loss – the ease in which a capability is fully developed before the onset of experience, but experience is necessary to maintain the capability.

Maturation – development of a capability independent of experience

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Perceptual Magnet Effect

Instances of sounds that belong to a category are drawn toward the Prototype.

Physical (acoustic) vs. perceptual maps– the latter differ for

speakers of different languages

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Can distinctions between non-native sounds be taught? Cheour has experimentally produced this

“development” In sleeping neonates Using changes in neural responses to

sounds as an outcome variable• http://www.med.cornell.edu/news/press/2002/

feb_22_newborn.html

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How sleeping babies learn

The babies had electrodes placed on their scalps, and speakers near their heads gently played a randomized sequence of two similar Finnish vowel sounds as they slept: a "standard" sound, /y/, and a "deviant" sound, /i/.

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Mismatch Negativity (MMN)

“ when the brain hears the standard sound, there is a certain response in the brain, and when it hears the deviant sound, there is another response.

Subtracting the responses to the deviant from the responses to the standard produces the MMN.”

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Training

No initial MMN for any group (N=15). Over the following night, for between

two-and-a-half and five hours, the experimental group had a "training" session of exposure to the two sounds.– /y/ vs. /i/.

One control group did not have this exposure, and the other control group heard two different sounds, /a/ and /e/.

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Results

The experimental group showed significant mismatch negativity to the deviant sound.

The babies had learned to distinguish between these two Finnish vowels.– Persisted for at least 24 hours.

The two control groups showed no MMN to the deviant sound.

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Conclusion

"We have shown that newborns can assimilate auditory information while they are sleeping, suggesting that this route to learning may be more efficient in neonates than it is generally thought to be in adults."

• Cheour

Is this learning?

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Reviewing the power of language

More maternal vocalizing at 1 month Associated with vocalizations at 8 & 24 months

and with socioeconomic status Also predicts greater adolescent intelligence

R2 = .22 for gazing and maternal vocalizations

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Long InfantFixation /

Low MaternalVocalization

Long InfantFixation /

High MaternalVocalization

Short InfantFixation /

Low MaternalVocalization

Short InfantFixation /

High MaternalVocalization

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Overview

Socioeconomic differences in how folks talk to their kids

What impact might it have? How is language experience associated with

later child language competence and IQ?

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Socioeconomic status differences in language experience are associated with later child language competence and IQ Meaningful differences in the everyday

experiences of young American children. Hart & Risley (1995). Baltimore, MD: Brookes Publishing Co

Some text from summaries by Susan Brunner, Dahra Jackson, and Amy Vaughan

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Participants

Longitudinal project from 9-10 months infant age up until 2-2 ½ years later– 42 families observed for one hour every month, at

home, in natural settings– recruited from birth announcements, friends and

families at University pre-school, WIC meetings, and state records

– all but 8 families were intact, all but one had a male figure involved

13 upper SES, 10 middle SES, 13 lower SES, and 6 families on welfare; all “well-functioning”

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Data collection

Observers transcribed and audio-recorded all verbalizations and interactions that would have an effect on another person; never interacted with child, but responded to parents– Observers assigned to families for entire study, when

possible, and similar to family in terms of background– no drop-outs after first year, reliability on coding and

observations was adequate– words coded as part of speech, episodes coded by type,

and speaker coded; dictionaries compiled for each speaker (all on computer)

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Commonality

Despite how strikingly different the families were in how much talking and interaction typically went on in the home, just socializing during everyday activities was sufficient for all children (regardless of SES) to learn to talk by age 3.

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42 Families and the Differences Among Them differences observed in family language style:

parents’ language seemed to reflect the number and variety of behaviors they had for dealing w/ their children

some families talked more than others, and this was variable within families from month-to-month, but stable over the 3 years– birth order and family size affected the amount of talk

each child received, but did not affect the total amt. of talk

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SES seemed to make the biggest contribution to both amount of talk and time spent in interactions, with hi SES at an average of 482 wds/hr and 48 mins/hr, and welfare families at 197 wds/hr and 17 mins/hr

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Language and SES (class)

Children from all backgrounds have the same kinds of everyday language experiences.

But more economically advantaged children differ in the amount of these experiences; it is the frequency that matters.

More opportunities for learning language occur when children engage in many and varied interactions with other people; families tend to be consistent in the opportunities they provide for their children.

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Talk that teaches talk

THEY JUST TALKED – parents talked beyond what was needed to provide care

THEY LISTENED– To add information and prompt elaboration

THEY TRIED TO BE NICE– When enforcing a rule

THEY GAVE CHILDREN CHOICES THEY TOLD CHILRESN ABOUT THINGS

– Things worth noticing or remembering (Halloween)

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Quantity of language: Nouns, adjectives, and adverbs to child

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Being positive

Repetitions, extensions, expansions, confirmations, praise, approval over all feedback (including imperatives, criticisms, etc).

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Relating things and events

Nouns, modifiers, and past-tense verbs divided by number of utterances per hour

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“Can you. . . ?”

Proportion of yes/no questions over yes/no questions and imperatives

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Responsiveness

‘Ok’ ‘I see’ % of responses not

preceded by an initiation

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How language experience is associated with later child IQ “Parenting” =

Language diversity + feedback tone + symbolic emphasis + guidance style + responsiveness

Predicts between and within SES groups

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Language experience makes the difference

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Implications for intervention

‘To intervene with vocabulary growth rate … increase the experiences available to the children

Limited success … ultimately the growth rates increased only temporarily.

Could easily increase the size of the children’s vocabularies, could not accelerate the developmental trajectory.’

“Removing barriers and offering opportunities and incentives is not enough to overcome the past, the transmission across generations of a culture of poverty.”

Is environmental influence global or specific?

We know that there are differences in language development across SES

Mothers are primary source of language-experience Does maternal speech mediate the relation between SES

and child vocabulary development?

The Specificity of Environmental Influence: Socioeconomic Status Affects Early Vocabulary Development Via Maternal SpeechErika Hoff

Maternal speech fully mediates relationship between SES and child vocabulary! SES -> 5% of variance in child vocabulary SES significantly associated with maternal speech MLU -> 22% of variance in child vocabulary

When removed, only 1% of variance explained by SES

So…there are 2 processes going on 1. SES affects maternal speech

Childrearing beliefs Time availability

2.Maternal speech affects language growth Provides data for child’s word-learning mechanisms

Longer utterance -> more variance in word types (richer vocabulary) Longer utterance -> more info about meaning Longer utterance -> richer syntax

Support environmental specificity model Vocabulary development depends on

specific properties of language experience Implies that enriching language experience

can increase vocabulary development for low-SES kids

Romero

Niparko et al., 2010

Romero

Earlier implantation, earlier language gains

Receptive Language

Romero

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Expressive Language

Higher parent-child interactions and higher socioeconomic status were associated with greater rates of language learning.

Bilateral implantation was not associated with an increase in language acquisition.

Gender was not associated with an increase in language acquisition.

Romero

Other findings