Language Development

Some definitions

Language - a socially shared code or conventional system for representing concepts through use of arbitrary symbols and the rule governed combinations of those symbols – Speech - a verbal means of communicating or

conveying meaning Gestural precursors to speech – and gestural forms

of speech

Questions 1

List and describe the two functions of crying? List and describe the major stages of pre-speech

vocalizations—phonation, cooing, expansion, canonical babbling, and integrative—using the audio samples from class as examples.

What types of vocalizations are produced in the expansion stage, why might infants produce them, and what are infants doing in producing them that (most) other animals cannot do?

What are characteristics of first words and what is the timetable for their emergence?

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Topics

Crying Pre-linguistic speech First word acquisition The vocabulary spurt

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Crying

Earliest vocalization –Curvilinear development at birth cry 1-1 1/2 hrs/day 6 wks cry 2-4 hrs/day 12 wks crying decreases Individual differences in quantity

Naturally occurring behavior– Then recruited for communication– Continuum of intentionality– Both directed and undirected crying still present at 12

months

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Two crying functions

“[N]aturally occurring cry in 26 infants – (aged 2.8-13.2 mo) and their mothers at home.

By 12 mo, most infants sometimes directed their crying toward the caregiver and elaborated the sounds by the use of gestures.

– But most continued to exhibit simple, undirected crying. Crying is both intentional and not intentional Shows increasing variability and sophistication in form

and function. • Gustafson, G E.; Green, J A. Developmental coordination of cry

sounds with visual regard and gestures. Infant Behavior & Development. 1991 Jan-Mar Vol 14(1) 51-57

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Different acoustic patterns

Basic hunger cry– rhythmic pattern of loud crying, silence, inhalation

Pain cry – loud, long shrill cry, then breath-holding silence

Fake cry low pitch and intensity, poorly articulated moans

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Crying judgments

Adults have some capacity to distinguish Judgment depends on care giving context as

well as acoustics Perceived aversiveness is important

dimension of judgments about meaning of cries

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Cries sound bad

There appears to be an underlying continuum of perceived aversiveness in young infants’ cries

That can be predicted by their duration, dysphonation, and proportion of energy in various frequencies

Parents and undergraduate non-parents perceive the cries as equally aversive.

• Gustafson, G. E.; Green, J. A. ‘Acoustic features of cry perception: Infant development. ’Child Development. 1989 Aug Vol 60(4) 772-780

Prelinguistic speech

Use of sounds in a communicative manner before speech (no words or grammar)

Progress through stages culminating in speech-like vocalizations– Phonation, Gooing, Expansion, Canonical

Some overlap in vocalizations characteristic of stages

• Kim Oller

Phonation Stage, 0-2/3 months

Vowel-like (“quasi-resonant”) Produced with normal speech like phonation

involving vibration of the larynx but with the vocal tract at rest– “comfort or pleasure” sounds - can sound like grunts

The infant’s tongue almost completely fills the mouth limiting the sounds newborns can make

Cooing/Gooing Stage, 1 - 4 months

Still vowel-like– /e/ & /u/ – but last longer

more guttural & throaty– produced in the back of the vocal cavity

thought to be precursors to consonants– /k/ /g/

Expansion Stage, 3 - 8 months

Isolated vowel-like sounds – Usually produced with the mouth open – Full vowels (“fully resonant nuclei”)

Vocal repertoire expands dramatically Infant experiments with sound production, varying pitch,

volume, & rate

Intentional communicative play– Already beyond pre-set animal calls

Which have set form and set causes

– Infant vocalizes for pleasure (just to have fun) or displeasure

Checking out the new sound system

Yells/whispers: playing with amplitude/intensity yells = high intensity, whispers = low intensity

Squeals & Growls: playing with pitch– squeals = high pitch, growls = low pitch

Raspberries – labial trill & vibrants

Cannot transcribe as adult syllables

Marginal babbles– consonant-vowel (CV) sequences – the transition between C & V is slow and drawn out– immature syllables

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Oller, K.

Functional flexibility of infant vocalization. Oller, et al. 2013. PNAS

‘Three types of infant vocalizations (squeals, vowel-like sounds, and growls) express a full range of emotional content—positive, neutral, and negative by 3–4 mos.– Contrast: cry and laughter are species-specific

signals apparently homologous to vocal calls in other primates, show functional stability, with cry overwhelmingly expressing negative and laughter positive emotional states.’

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‘Functional flexibility is a sine qua non in spoken language Appears before syntax, word learning, and

even joint attention, syllable imitation, and canonical babbling. The appearance of functional flexibility early in the first year of human life is a critical step in the development of vocal language and may have been a critical step in the evolution of human language, preceding protosyntax and even primitive single words.’

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Canonical Babbling Stage, 6-10 mos

CV sequences – /ma/ /da/ /ada/

Transition between CV are crisp – Sounds like natural syllables in parent’s language– Parents good at identifying this stage

Reduplicated babbling – /baba/ /dadada/ /mama/

Importance of Babbling

Involves increasing control over the articulatory mechanism

Important pre-speech developmental milestone Should be present by 10 months!

– Occurs in Down Syndrome, premature, low SES kids and in all cultures

– But its delayed in hearing impaired infants and deaf children

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Limitations of Babbling

At end of stage, infants begin to use patterns or rising intonation that resemble adult speech– also known as gibberish, jargon, or conversational

babbling– It has intonation contours of language being learned – Infants learn the music before the words

Does not refer (to objects, people, etc.) Is not language

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Integrative stage (9-18 months)

Beginning of meaningful speech Some mixing of babbled utterances and

words Gibberish: (jargon) use of adult intonation

patterns but what they say makes no sense– sounds like the child is having a conversation

but you can’t understand what they are saying

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First word definitions

Function– They are first words because they refer– Arbitrary sound is paired with an object– Often but not always nouns in the environment

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First Word Characteristics

Form– Conventional– Typically brief

1 syllable, e.g., ‘no’ or a reduplicated syllable, e.g., ‘ma-ma’

Most linguistically common words– May be developed by babies– And may be the easiest to articulate

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First Word Timetable

Appear– Typically: 11 to 13 months– Normal range: 10 to 14 months

Normal variation– 13 month vocabularies: 0 - 45 words– Should have first word by 15 months

Screen for delay

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First 50 words

Represent all of the major grammatical classes found in adult language

- nouns: dog, cookie- verbs: down, up, eat- adjectives: hot, dirty- social words: yes, no, please- sound effects: meow, ouch, uh-oh

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Cross-cultural differences in first words acquired

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How words are learned

Reference: Pairing of object names with objects Child must visually attend while label is provided

– So receptive joint attention helps– Helps if parent labels what child is already looking at– May be facilitated by routines

Metalinguistic insights – “Things have names” “I can make things happen with

words”– Corresponds to vocabulary spurt

Rapid, accelerating growth

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Nouns

Most common throughout language development

Why do infants learn nouns most rapidly?– Adults tend to label objects more than they

label actions (fly, run) or describe objects (yellow crayon)

– Verbs are conceptually more complex; nouns are concrete where verbs tend to be more

abstract

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Vocabulary Growth

Slow at first– can take 3 or 4 months after first words to

achieve a vocabulary or 10 to 30 words 18 month infant

– typically has a vocabulary of 50 words 18 - 22 months

– Vocabulary spurt – From 50 to 300 words in few months

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Meta-linguistic insights

Things have names” Corresponds to vocabulary spurt

Rapid, accelerating growth

“I can make things happen with words”– Effort to express/understand participate– Intentionality model (Bloom)

Language learning is effortful

Receptive and Expressive

2 types of vocabulary development– Receptive - understands others’ words

Say ‘bye-bye’. ‘Where’s Daddy?’ 13 months - 50 words

– Expressive - total words used (productive) Receptive typically outpaces expressive

– Child understands more words than they use

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Individual Differences

2 styles of language– Referential style - use language primarily to

label objects in their environment E.g., dada, doggy, baba

– Expressive style - use language as a means for engaging in social interaction

Hi, bye, ut-oh– More kids have an expressive style although

most have a combination

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Syntax = grammar

Evidence of syntax – Nonrandom combinations

Development of syntax– Takes place with no explicit instruction.

Parents may teach new words but don’t teach syntax. `The emphasis is on what the child is saying rather than how

the child says it.

Innate or modeled?

Syntax of one word speech

Holophrase - a single word used to express complex meanings– “Cookie” = “Give me the cookie” – Early utterances are telegraphic

The essential words are used to convey whole ideas

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Syntax of 2 word sentences

Emerge – 15 – 24 months, mean is 18– Usually have 50 words in vocabulary before combining

words 7 months after their first words

First sentences typically consist of nouns, verbs & adjectives

– Uses: name, locate, negate, question, etc.– Pivot word

frequently occurring word attached to a variety of other words More: Mommy, milk, hug

Common Errors

Underextension– Word refers to particular exemplar– “Car” = family’s car

Overextension– Word refers to inappropriately large class– “Car” refers to all big things with wheels

Interplay between two yields correct word usage

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Measuring grammatical development Mean length of utterance (MLU) is a measure of

syntactic development. Average length of the child’s utterances is

calculated in morphemes - NOT WORDS– a morpheme is the smallest unit of meaning in a word

free morpheme: can stand as a word by itself (e.g., kind) bound morpheme: exists only within a word (e.g., -ly, -ness, -

s, -ed, ‘s) Each new morpheme reflects new linguistic knowledge. “I running” = 3 morphemes (not 2 words)

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MLU length

Children who have similar MLUs are at the same level of linguistic maturity, and their language is at the same level of complexity.

Children have MLUs of 1.0 to 2.0 1-2 years 2.0 to 3.0 2-3 years 3.0 to 4.0 3-4 years

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Comprehension: Gogate

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Comprehension: Gogate

Motherese/child directed speech

Most adults can do it, infants prefer it Parents speak for children Parents stay a step ahead of child (scaffolding) Aids in teaching the child the norms of their

culture & rules of their language – cultural differences stem from mother’s styles of

interactions and child rearing beliefs

Has positive affect on early language development

Infant directed speech

Slower rate, higher pitch, longer pauses– Repetitive & reduplicated

Brief, grammatically correct sentences– Use of simple syntax

Key words at end & are spoken in a higher & louder voice– Diminutive used

Vocabulary is concrete– Objects may be over described

https://www.youtube.com/watch?v=cSCXMfeo74Q

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Children’s early comprehension of syntax Assessment methods involving action such as

– diary studies (parents document conditions under which the child can or cannot understand)

– act-out tasks (in which the experimenter asks the child to act out a sentence using toys)

– direction tasks (in which the child is asked to carry out a direction, such as “tickle the duck”)

– picture-choice tasks (in which the child must select the picture that best represents the linguistic form being tested)

Have limitations leading to confusion about children’s comprehension abilities.

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The preferential looking paradigm Has helped clear things up.

– Used to assess language comprehension in infants as young as 12 months.

– Child watches two simultaneously presented videos. – Child hears a statement describing one of the videos – Record the amount of time the child spends watching

each video– Repeat

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Child hears

“Cookie Monster is tickling Big Bird” – one screen showed Cookie Monster tickling Big Bird – One screen showed Big Bird tickling Cookie Monster.

Children at 17 months of age spent more time looking at the screen that matched the statement.

Children can comprehend word order before they even begin using two-word sentences.

Suggests that comprehension is indeed in advance of production, as parents have always known.

Statistical learning

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Statistical rules Learning

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How Is Language Learned?

Theories of language development

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Learning Theory

Language is learned through experience. Emphasis on role of child’s environment– Reinforcement ~ Parents reinforce or reward infants

babbles that are approximations of real words (B.F. Skinner).

shaping ~ children acquire early vocabularies through shaping or when parents require children’s utterances to be progressively closer to real words before reinforcement

role of imitation ~ parents serve as models & children learn language in part through observation & imitation (Bandura)

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Learning theory cannot explain:

why children spontaneously utter words or phrases they have never heard

why there are invariant sequences of language development

why there are spurts in language acquisition

Nativist Theory

Innate factors cause children to attend to & acquire language– Chomsky’s psycholinguistic theory

Environmental regularities cannot account for the consistency of language acquisition.

A neurally based language acquisition device is at work, enabling innate understanding of deep structure of language.

Evidence for an inborn tendency:

Verbal function is localized in speech centers– Typically in left cerebral hemisphere– There is plasticity– But it diminishes with age– Sensitive period ~ proposed by Lennenberg; beginning at 18-24

months & lasting until puberty neural development facilitates language learning Genie

Universality of human languages– invariant sequences in development– newborns respond to language– regularity of early production of sounds

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Nativist theory does not explain:

variance in language skill & fluencey how children understand the meanings of

words why language develops best when there is

another person to communicate with

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Review Syllabus