Child Language Acquisition by dfhdhdhdhjr

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									CHILD LANGUAGE ACQUISITION




Group 5           07305037 Shitanshu
Verma
               07305086     Rajeshwar G
               07305905    Girija Limaye
               07305913   Apoorv Sharma
MOTIVATION
QUESTIONS
    When does a child starts listening ?
    If child is left alone with a deaf mother will it learn ?
      o Akbar’s experiment

    If we try to make a chimp available to all the inputs will
     it learn ?
      o Obvious no, but what makes humans unique

    You must have observed
      o For a child a dog is any four legged animal

      o For a child a city is just the home he knows in the city

      o Child never misplaces

    Do you know:
      o Children don’t like when we talk to them in motherese

      o Children understand more phones than adults
IF WE UNDERSTAND THE PROCESS
   Fields it will benefit
    o Psycholinguistics
    o Neural Networks
    o Psychology
    o Statistics
   Get insight into brains of humans
   Compare with other animals
   Understand the mental representation

   Why a seminar in NLP course?
    o   teach the machines the same way

              TILL NOW IT IS UNEXPLAINED
IN THIS PRESENTATION
   Broad coverage of various aspects of child
    language acquisition studies
    o Observations
    o Theories

   Scope and Roadmap
    o Fundamentals
    o Human’s special affinity to language
    o Stages of child language acquisition
    o Theories explaining CLA

   We would not talk (much) about
    o   Specific theories explaining individual stages
         Eg. Motor Theory Account
Basics and Biological Human
Adaptation
LANGUAGE
   Language
    o Grammar
    o Vocabulary
    o Recursive

   Animals communicate
    o Have sounds
    o Special meanings to sounds
    o Unique to humans

   Seems it is innate to humans
    o   Seems !
CHILD LANGUAGE ?
INNATENESS – BIOLOGICAL
DEVELOPMENT




The infant's vocal tract resembles that of a chimpanzee!
   o Indistinct oral and pharyngeal cavities
   o The soft palate (velum) reaches the epiglottis
This facilitates breathing through the nose while suckling
   o By three months the larynx descends into the pharynx
   o Allows greater range of speech sounds
   o Increases the risk of choking
BRAIN – DEVELOPMENT AND
SUPPORT TO LANGUAGE
   Linguistic capability require
    o   Minimum levels of brain size
    o   Long-distance connections
    o   Extra synapse
    o   These are developed highly during first few years in
        children
    o   Infant body is very plastic
 Left hemisphere surrounding the Sylvian fissure,
  that appears to be designed for language
 High cognitive capabilities
    o   Sound and speech : Use broad pitch and rhythm
        efficiently
STAGES OF CHILD
LANGUAGE ACQUISITION
Observing a child grow 
WAY WE CAN STUDY
   Various aspects and ways
    o Perception development
    o Speech development


    o Focus on phonological development
    o Focus on meaning understanding development
    o Focus on grammar development
    o Individual studies on them



   We will be doing a mixture of these
PRE-BABBLING(VERY YOUNG)‫‏‬
   Pre-equipped to head phonetic contrasts
    o   even for languages not spoken around them
   later become insensitive
    o   At 10 to 12 months
    o   Seem to be discovering phonemes
   Infants can distinguish between /p/ and /b/ at
    three or four months
BABBLING(4-6 MONTHS)

 Using indiscriminate utterance of speech sounds
 Utterances may be other than native language

 Very few consonant clusters

 Repeated syllables are common
PERCEIVING PHONEMIC
DISTINCTIONS

 Differences between the sounds of different languages
  Both Hindi and English: /ba/ vs.       /da/
     6-8 month-old babies and adults could discriminate
     o
  Hindi, not English, easy /Ta/ vs.        /ta/
     o 6-8 month-old babies could discriminate.
     o Adults could not initially but could after 25 trials of training.

    Hindi, not English, /th/        vs.       /dh/
     o   6-8 month-old babies could discriminate.
     o   Adults could not, and never learned
    Babies can discriminate the sounds of all the world’s
     languages and adults cannot
Perceptive Development

 They   show high cognitive abilities
 Children    can discriminate between
      Human speech from other sounds and prefer to listen to it
      Their mother’s voice and other adult women’s voice
      Infant directed speech from Adult directed speech
      Mother Tongue from Other language
RECOGNIZING AND REMEMBERING
WORDS

 6 to 7.5 months
   olearn to identify familiar words in context
 7.5 months

   oEnglish-learners can identify words with
   strong-weak stress patterns
 10.5 months

   o Can identify words with weak-strong patterns
 Common words are remembered more
Recognizing and Remembering Words
 Nouns before verbs
 Content verbs before auxiliary verbs

 Meanings are over generalize or under
  generalized
   o City name
      o only the house they visit in city
   o Dog
      o Any four legged animal
 The ends of words learned more quickly

   o -nana for banana.

   o true even in language where the stress in
     always on the first syllable.
HOLOPHRASTIC (1 YEAR)‫‏‬

 Utter their first word as early as nine months
   o Mama

   o dada (these words resemble babbling)‫‏‬

 Often the words are simplified

   o "du" for duck

   o "ba" for bottle

 First words of children are common throughout
  the planet
    o food, body parts, water, toys, mama, etc
    o then routine words used in social interaction
        yes, no, want, bye-bye, hi
TWO-WORD STAGE(18 MONTHS-2 YEARS)

   Sentences are of limited meaning
    o ownership-- Daddy's shoes
    o describing events-- Me fall
    o labelling-- That dog
    o vocational relations-- toy in box

   Children design pivot grammars
    o Prefer certain words - pivotal (axis) words
    o Use different words with the pivots to create phrases
LEARNING THAT ELEMENTS ARE ORDERED


   Infants
      oRarely scramble the order of words.
      oHear more to their mother tongue
      oElder babies could find distance dependency
            The boy, who I like, is here today
     oSensitiveto the statistical properties of what they hear
          Develops before and during infancy
 DOES THIS MEAN THAT BABIES
 ‘KNOW’ GRAMMAR ‘INNATELY’?

 Younger babies could not do this, though some
  experiments found that they could do a related but much
  simpler task at 7 months
 Babies are sensitive to the statistical properties of what
  they hear and these sensitivities are developing before
  and during infancy.
FURTHER DEVELOPMENT(AFTER 18
MONTHS)

 Begins to form longer utterances
 Lack grammatical correctness but the meaning is
  conveyed
 Some examples
    o dirty hand wash it
    o car sleeping bed = the car was now parked in the
      garage
 Inflection is learnt by the age of 3
 Look for phrases to built upon the rules of the
  language
 The sentences become more lengthy and
  grammatically complex afterwards
EXPLAINING CHILD
LANGUAGE ACQUISITION
Theories on Child Language Acquisition
THEORY – CLASSIFICATION
   On basis of principles
    Nature
    o
      brain has innate propensity for CLA
  o Nurture
      CLA is general cognitive ability
      no specific biological evolution
o None is fully in opposition to other
        oWhich is dominant factor
THEORY – UNIVERSALLY ACCEPTED
FACTS
   The basic ability to acquire language is innate to
    the child
     o Needs external trigger
          Akbar’s experiment
 Intelligence is not related with L1A
 No specific structural property of language has
  yet been proven to be innate
THEORY – OPEN ISSUES
 None explains all the observations
 Is it modularity of brain?
 Is it native to brain?
   note difference between nativism and
   modularity
 L1 competency is better than L2 competency
 L2 acquisition at different extent
Some Popular Theories
 Cognitive
 Imitation and positive reinforcement
 Innateness
 and others like Motherese
COGNITIVE THEORY

   Nurture
    o   No special part of brain promotes LA
   Introduced by Piaget
   Language acquired attributed to
    o   general intellectual development
   Process
    o   acquires concepts
    o   concept -> word mapping
           natural cognitive development
COGNITIVE THEORY

   Suggests
    o   simpler ideas learnt earlier
    o   irrespective of grammatical complexity
   Explains
    o   order of certain aspects of LA


   Does not explain
    o Why languages emerge?
              Cognitively found in animals, but they don't acquire
              language
    o   Studies: Despite abnormal mental development,
        children speak fluently
Inputs to Child Language Acquisition
    Positive Evidence
     o information available for correct grammatical

       structures
    Negative Evidence
     o information available for incorrect
       grammatical structures
    Motherese
     o modified language used by parents

    Prosody
     o Melody, timing and stress

    Context
     o Learns only with help of context

     o Never learn from radio or television
IMITATION AND POSITIVE
REINFORCEMENT
 By imitating adults and repeating what they
  hear
 Limitations:
    o   Based on observations
   Unanswered:
    o Mistakes: indicate application of rules, not just
      imitation (intelligent mistakes)‫‏‬
    o Feedback
           Governed by Truth value rather than syntax
POVERTY OF THE STIMULUS
   Claim
    o   Grammar is unlearn able given the linguistic data
        available to children.
   Premises
    o Limited input signals received
    o The degenerate nature:
         frequent incorrect usage, utterances of partial
        sentences
    o Patterns that cannot be learned using positive
      evidence alone.
   Conclusion
    o   Child must have some form of innate linguistic
        capacity.
INNATENESS
   Innate capabilities of language learning
    o   Language Acquisition Device
           assumed to have Syntactic structures
    o   They only learn words
 Explains intelligent mistakes (with LAD)
 Limitations
    o Only focus is on grammar
    o Syntactic structures: Language dependent, Innate??
    o Explaining LAD?
LANGUAGE ACQUISITION DEVICE
 Supposed to be an Organ of brain
 Intractable complexity of language acquisition

 Assumed Components
    o   technique for representing input signals
    o   a way of representing structural information about
        them
    o   some initial delimitation of the class of possible
        language structure hypotheses
    o   a method for determining meaning of hypotheses for
        each sentence
LANGUAGE ACQUISITION DEVICE
   Steps
     o Input signals --> structural information
     o Checks the compatibility of input with the
       hypothesis
     o Checks the compatibility using knowledge of
       implications for each hypothesis
     o One hypothesis or ‘grammar’ is selected as
       being compatible with the input signals.
     o This grammar provides the device with a
       method of interpreting sentences
Conclusion
 Humans do have a better biological evolved body
  for language
 Certain traits such as sound processing are
  innate to infants
 Children learn language remarkably fast

 Interesting patterns are present in child
  language acquisition process
 Various theories have been proposed
     None explains all
     Nature vs Nurture is the prime issue
References
 www.wikipedia.org
 Language Acquisition, Steve Pinker, Draft
  version
 pandora.cii.wwu.edu

 Language Acquisition, Elena Lieven, School of
  Psychological Sciences,University of Manchester
 Language Acquisition, Michel Frank

								
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