Language DevelopmentLecture Notes: 11/4/14The Language Gene(s)?● Three generations of the KE family (14 of the 29 members) have a speech and languagedeficit○ Their speech is poor, almost unintelligible○ They are impaired in reading, writing, language comprehension, and use of grammar. Their IQ is lower on average than of the unaffected family members, although there is enough overlap to exclude this as the cause of the language deficits○ They have difficulty imitating mouth and face movements○ Also, difficulties with procedural memory (memory for skills)● Genetic studies traced the abnormality to the mutant FOXP2 allele on chromosome 7The Role of Input in the Development of Grammar● In some cultures, pre-verbal children are not talked to; yet, children acquire language (including its grammar)● So is input really not important?● Evidence that input contributes to grammatical development○ Prosodic cues to sentence structure○ Amount of input correlates with rates of grammatical development○ Mothers’ repetition and expansion of children’ utterances correlates with grammatical development● But….evidence that input does not contribute to grammatical development○ Children overgeneralize, and this overgeneralization cannot be based on the input○ Children also stop overgeneralizing. Why?○ There is very little evidence that overgeneralization and recovery● But…○ Adults are more likely to repeat children’s utterances if they are grammatically correct○ Adults are more likely to ask for clarification for ill-formed sentences○ Adults recast the incorrect productions○ Children are sensitive to this feedback, and are more likely to attempt a correctedproduction after the adult’s recast● But…○ This input is not consistent, and by some estimation, a child would have to say the same sentence ungrammatically 85 times to have enough data from their parent to conclude that it is, indeed, ungrammatical● Together: There is something about the input that influences children’s grammatical development. However, it may not be sufficient to explain children’s development of grammarSo, is language modular, domain-specific?● Piaget: cognitive development drives language development● Symbolic thinking, memory, attention, pattern analysis feed into language development● Categorical perception is not specific to language or to humansSo, is there really no “negative evidence?”● Adults repeat correct productions, and recast the incorrect ones (they certainly never repeat the incorrect production)The Nature/Nurture Debate● May not be a debate, at all● Most scientists agree that something about language is innate● However, most scientists also agree that linguistic input plays a major role in language developmentInteractionist Approaches to Language Development● Language and Cognition (Piaget)● Language and Society-Culture (Vygosky)● Language and Its Social Function (Elizabeth Bates)● Usage-Based Theory of Language Acquisition (Michael Tomasello)Language as an Outcome of Cognitive Development● Associated with Jean Piaget’s theory of cognitive development● Language is seen as a skill that develops as a result of cognitive maturation, through theinteraction between the child’s cognitive abilities and the linguistic environment● Children express only those things that they understand (i.e., no concept, no language)○ E.g., prior to object permanence- the world is experienced only through direct interaction with it; after object permanence- can think about objects that are not visible, and can therefore learn words○ E.g., understanding that animate objects act on the inanimate objects → production of Subject Verb Object sentences● But...just because things happen at the same time, does not mean that they are causallyrelated● Moreover, dissociation between cognitive and linguistic development have been notedLanguage as an Outcome of Social-Cultural Environment● Associated with Lev Vygotsky● A child’s development is determined by the social interaction and collaborative problem-solving● Zone of proximal development○ The distance between the actual development level as determined by independent problem solving and the level of potential development as determined through problem solving under adult guidance● Scaffolding○ The help provided by the caregiver to get the child to the “potential” developmental level● In development of language: raising the bar on what counts as communication and internalization of language● Language starts as a tool used for social interaction. Children use language to obtain thehelp of others and solve problemsLanguage as an Outcome of Communication = Social-Interactive Approach● Combines behaviorist approach (the role of environment) and nativist approach (linguistic rules are unique)● Maturation is seen as crucial for the development of language (i.e., children have to be “cognitively ready”), but the environment is necessary for its emergence● Structure of the child’s emergent language is the result of its social-communicative function● Child and the environment form a dynamic system where child evokes linguistic input and uses the input to update her linguistic knowledge● Greatest source of linguistic input = Child-Directed SpeechMechanisms of Social-Interactive Learning: CDS and Meaning-Making● CDS teaches the child how to produce sounds (through exaggeration); it helps vocabulary development (through focusing on the objects the child is attending to); it informs grammatical development (through simplified grammatical input).● Interaction with the parent teaches the child the basics of conversation; meaning-negotiations between the parent and the child form children’s first concepts; social conventions (thank you) are taught● The child has innate predispositions for language learning; the environment is constrained to enable the child to have the experience required by these innate predispositions● Social interaction ←→ Language developmentUsage-Based Theory of Language Acquisition● Two sets of skills are important for language development● Intention reading○ Ability to share and follow attention of other people (objects and events)○ Ability to direct attention of others○ Ability to learn the communicative intentions of others■ These are unique to humans○ Foundational skill that underlies children’s linguistic