Language Development in Special Populations 31925_27MAR_APR08
Topic breakdown A. Deficits in sensory motor system (pp 296-307) Language development and deafness/hi Language development and blindness B. Deficits in general cognition: Language development in MR/ID populations (pp 307-317) Down Syndrome Williams Syndrome C. Deficits in emotional/social domain (pp 317-320) Language development and Autism D. Deficits in language abilities (pp 320-331) Specific Language Impairment
Why Study Special Populations? Applied concerns Basic research concerns Theories of language acquisition and: Sensory systems General cognitive abilities Social-emotional abilities Is language learning domain-specific or domain general? The case of SLI
Concepts Mental age vs. chronological age comparisons Mental age = mental maturity level - often measured by performance IQs Language level vs. age level comparisons Language level matching often = MLU Matching can be both age (mental or chronological) and language level
Concepts ND = normally-developing; TD = typicallydeveloping Normal curve: 1.25 standard deviations or lower = lower than normal range people first language Children with SLI vs. SLI children Children with autism vs. autistic children
Deficits in the Sensory Motor System Language development and deafness Language development and blindness
Language Development and Deafness/HI Deaf of deaf and deaf of hearing Hearing impairment vs. deafness Mild, moderate, sever an profound Etiology of HI
Language Development in Deaf of Hearing Children How do they learn language? Oralist method Intensive training in lip-reading/speech-reading Total communication Lip-reading & manual gestures Bilingual-bicultural ASL immersion with English as a second language (oral and written) Deaf culture valorized
English Language & Literacy Development in D of H Phonology: can be quite unintelligible Misarticulation, word final sound deletion, CCR Lexicon: vocabularies significantly smaller than chrono age TD peers. Morphosyntax Difficulties with complex sentences & grammatical morphemes Degree of HI makes a differences Low literacy skills Theoretical implications: Critical period for L1
Writing Sample from Child born Deaf We went to family camp today. She will be good family camp dog food. Boy went family fun dog friend car look. The played outuroor camp family good eat afternoon. The played eat fun camp after home. We perttey fun camp after home. The will week fun camp after car. We family will eat and afternoon. [10-yr-old boy; performance IQ of 129; born deaf]
Cochlear Implants Device to bypass defects in inner ear HI children achieve significantly better results in oral and written English with implants Early age of implant important (critical period) Controversial - Deaf culture
Acquisition of Sign Language: Deaf of Deaf Theoretical Questions: Is language development set for the auditory modality? Is gestural/iconic communication easier? Phonology Petitto & Marentette (1992): manual babbling at 6-12 months Location, handshape and movement:
Acquisition of Sign Language: Deaf of Deaf Lexicon First signs earlier than first spoken words? Content of early sign vocab = word vocab? Iconicity: Are iconic signs easier to acquire?
Acquisition of Sign Language: Deaf of Deaf Morphosyntax Pronoun reversals Two-sign stage Is language development set for the auditory modality? Is gestural/iconic communication easier?
Language Development and Blindness Theoretical question: What is the role of visual images and interaction (eye gaze) in acquisition? Phonology speech sounds that have visible properties: Lexicon Touching vs. seeing: Morphosyntax Delay in auxiliary verbs Reliance on routines
Deficits in General Cognition Language development and Mental Retardation/Intellectual Disability
What is Mental Retardation/ID? IQ 40-70 Down Syndrome Abnormality = a third chromosone 21 1/800 children Fragile X syndrome Mutation of FMRI gene on X chromosone Williams Syndrome Abnormality on chromosone 7 (several genes) 1/20,000-50,000 children Theoretical question: What is the role of general cognition in language development?
Language Development in Children with Down Syndrome Phonology Delay in sound production: < mental age Lexicon First word = 24 mos Variation in vocab size: mental age Word Learning processes = ND children Morphosyntax Very delayed: < mental age
Language Development in Children with Down Syndrome Communicative competence Relatively spared Language development in DS children and the role of general cognition in language acquisition:
Language Development in Children with Fragile X Co-morbidity with autism Phonology Particularly affected: Harsh speaking voice; stuttering Lexicon & morphosyntax Delay - similar to mental age matches Expressive/receptive asynchrony Communicative competence Delay - similar to mental-age matches Language development in FX children and the role of general cognition in language acquisition:
Language Development in Children with Williams Syndrome Speaks directly to cognition in language question? Lexicon Vocab size = mental age; sometimes = chronological age Phonology: articulation relatively spared Morphosyntax Deceptive syntactic skills - appearance of fluency
Drawing (visual-spatial) vs. Speaking
Narrative abilities: WS compared with DS Once upon a time when it was dark at night the boy had a frog. The boy was looking at the frog sitting on the chair, on the table, and the dog was looking through looking up to the frog in the jar. That night, she sleeped and slept for a long time, the dog did. But the frog was not gonna go to sleep. The frog went out from the jar. And when the frog went out the boy and the dog were still sleeping. Next morning it was beautiful in the morning, It was [WS, age 17, IQ = 50] The frog is in the jar. The jar is on the floor. That s it. The stool is broke. The clothes is laying there. [DS, age 18, IQ = 55]
Language Development in Children with Williams Syndrome Communicative competence: relatively spared (like DS) Explanations for WS children s language performance: memory? Do WS syndrome children prove language and cognition are separate?
Deficits in the Emotional/Social Domain Language Development and Autism
What is Autism? Neurologically-based, not environment Autism Spectrum Disorder: Deficits in communication, social interaction, repetitive/stereotyped behaviours and interests Onset/diagnosis = 30 mos Verbal vs. non-verbal, co-morbidity with MR: Low-functioning vs. high-functioning Theoretical question: What is the role of social interaction/communicative competence in language acquisition?
Language Development in High- Functioning Children with Autism Phonology Segmental vs. suprasegmental = chronological age Lexicon Relative strength: mental age Morphosyntax MLU growth = mental age New research suggests more deficits in morphosyntax in Autism
Language Development in High- Functioning Children with Autism Communicative competence Deficiencies in joint attention, indirect requests and speech acts Discourse skills limited, and < structural skills
Theory of Mind and Autism Theory of Mind: to be aware of the mental states of others; the ability to attribute different mental states to others Theory of Mind crucial to development of communicative competence Children with Autism lack full theory of mind?
Deficits in Language Abilities Specific Language Impairment
What is SLI? SLI = developmental language disorder, developmental dysphasia Affects 5-7% general population Children with SLI: delay in phonological, lexical and discourse-pragmatic abilities; deviant in morphosyntax SLI is a life-long disorder Theoretical question: how independent is language from other cognitive systems?
Lexicon SLI in English Vocab size < ND chronological age Morphosyntax MLU < ND chronological age (approx 2 yrs) Grammatical morphology < language matched younger age Pragmatics/communicative competence: Areas of most profound deficits shift during school years
Child with SLI at 4;3 (Leonard, 1998) EXP: okay, ready? CHI: ready. EXP: this is Jim. Tell me a story about Jim CHI: him going fishing. Jim hold..water. And go fish. EXP: this is Kathy. Tell me a story. CHI: Kathy brush teeth. Her eat. And her get clothes on. EXP: she must be getting ready to go to school, huh? EXP: This is a woman and this is CHI: boy. (correct = a man) EXP: the woman is washing dishes and CHI: boy is painting. (correct = a man is painting) EXP: he s zipping his jacket. What did he do? CHI: zip jacket. (correct = zipped his jacket) EXP: she s combing her hair. What did she do? CHI: comb hair. (correct= combed her hair)
Diagnostic Criteria for SLI SLI = subcategory of LI Primary language vs. primary speech impairment Exclusionary criteria No frank neurological damage No hearing loss Normal IQ No severe social-emotional problems Inclusionary criteria Discrepancy between verbal and nonverbal IQ Score 1 SD below mean on standardized language test
Is SLI Delay or Deviance? Delay Rice (2003): receptive vocabulary and tense marking growth curves = same shape as TD
Vocab and Tense Growth Curves
Is SLI Delay or Deviance? Delay Rice (2003): receptive vocabulary and tense marking growth curves = same shape as TD Deviance Unique errors? Unique learning mechanisms? Unique error profile compared to language levelmatched, TD children: 3N vs. SLI for tense (3S-s) and for non-tense (plural -s)
Focus on 3N and SLI for Tense
Tense vs. Plural: SLI vs. 5N & 3N
Is SLI Delay or Deviance? Delay Rice (2003): receptive vocabulary and tense marking growth curves = same shape as TD Deviance Unique errors? Unique learning mechanisms? Unique error profile compared to language levelmatched, TD children Can delay and deviance both characterize SLI? Rice (2003): disruption-within-delay
Train Metaphor
How Specific to Language is SLI? Children with SLI score in low normal for nonverbal IQ Children with SLI show deficits with TD age matches: spatial cognition response times in linguistic and nonlinguistic cognitive tasks Verbal working memory
Crosslinguistic SLI SLI affects grammatical morphology in all languages studied, but different aspects Germanic languages: Romance languages: Highly-inflected languages = more commission/substitution errors than in English
What Causes SLI?
Nature or Nurture? Very little evidence for environmental factors in SLI Input? Substantial evidence for genetic component in SLI Children with SLI 20-25% chance of immediate family member with language disorder; 3% for TD children Familial concentration: the K family
SLI as a Deficit in General Cognitive Processing SLI = limitations in information processing: Predicts across-the-board delay in language; implications for cognition Nonlinguistic cognitive limitations same source as linguistic limitations in SLI Problems with this account:
SLI as a Deficit in Linguistic Representation SLI = selective deficits in ability to establish specific properties of language (e.g. faulty UG is part of the problem) Predicts SLI effects NOT across-the-board in language Predicts deviance in SLI (not just delay) Predicts some crosslinguistic universality Problems with this account: