Language Development in Infancy Chapter 9 Systems of Language Phonology: sounds that are linguistically meaningful Semantics: meaning of words Syntax (grammar): rules for arranging and combining words Pragmatics: everyday rules of language Theory B.F. Skinner (Empiricist): children s language learning is similar to how they learn other behavior through imitation and reinforcement Noam Chomsky (Nativist): lanaguge acquisition develops because of an innate predisposition; naturally occurring language is too complex to develop through simple learning rules 1
Evidence for Empiricist View Children learn language that is spoken around them The amount and variety of early exposure to language is predictive of later acquisition of semantics and grammar Children learn about pragmatics from language experience Parents frequently modify their speech to simplify it for infants Evidence for Nativist View Children progress through the same prelinguistic stages as they learn language Children make errors they never heard in adult speech Children are able to apply rules of grammar to words they never hear before Deaf children being reared without exposure to formal sign language invent their own rule-governed gestural system of communication Stages of Language Production 6-8 months: babbling 10-12 month: one-word stage 2 years: two-word stage 2
Comprehension and Production Receptive Language: language comprehension 50-word milestone around 13 months Expressive Language: language production 50-word milestone around 18 months Receptive Language Expressive Language Vocabulary burst: rapid increase in receptive and expressive language during the second half of second year (18+ months) 3
Methods for Studying Language Observation in natural setting with and without mother More language production when interacting than alone but most production during optimal language situations Methods for Studying Language Questionnaires and structured tasks MacArthur Communicative Development Inventories Reynell Developmental Language Scales Methods for Studying Language Conditioned head turning procedure Auditory preference procedure Preferential looking Habituation Brain measures (ERP, NIRS) High quality recordings of infant speech 4
Infant/Child-Directed Speech Prosodic features: higher pitch, greater range of frequencies, more varied and exaggerated intonation Simplicity features: shorter utterances, slower tempo, longer pauses between phrases, fewer embedded clauses, fewer auxiliaries Redundancy features: more repetition over shorter amounts of time, more immediate repetition Lexical features: special forms like mama Content features: restriction of topics to the infant s world Infant/Child-Directed Speech Is mostly universal Elicits attention Modulates arousal Communicates affect Facilitates language comprehension Watch video: https://www.youtube.com/watch?v=atyojru7ajy Turn-Taking (Protoconversation) Timing and waiting for one s turn in conversation has roots in adult infant interaction Parents typically vocalize rapidly after an infant vocalization, and they often prolong pauses after their own vocalizations to increase the likelihood that infant vocalizations will become part of a conversational chain Watch video: https://www.youtube.com/watch?v=t4pyu-61n2g 5
Gesture: nonverbal communication Starts around 8-10 months Joint Attention: when two people are attending to the same object or event Labeling When labeling objects, parents show the tendency to move the object in synchrony with their verbal label Labels are usually the loudest word in a sentence Labels are typically only given when infant attending to object being labelled 6