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Phonological Development

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  1. Phonological Development Ages and Stages

  2. Discussion Outline • Normal Developmental Stages • Developmental Norms • segmental norms vs phonological processes • Theories of Phonological Acquisition • Cognitive Model of Phonological Acquisition • Components of Early Phonological Development • Differences in Assessing Early vs Later Phonological Abilities

  3. Discussion Outline (continued) • Types of Analyses • Independent + Relational • Profile of Typical 2 year old • Who are Late Talkers? • Profiles of “Late Talkers” • Rescorla & Ratner • Williams & Elbert • Develop a Protocol for Late Talkers

  4. 4 Stages of Development • 1. Prelinguistic (0 - 1 year) • reflexive vocalizations • cooing • vocal play • babbling • variegated babbling

  5. 2. First Words (1 - 1.6) • Whole-word strategy • Unanalyzed “wholes” • Progressive idioms

  6. 3. Phonemic Development (1.6 - 4) • Rule-governed strategy • 50 word vocabulary

  7. 4. Stabilization • Acquisition of later sounds

  8. Developmental Norms • Segmental acquisition studies • Phonological process norms

  9. Universalist-Linguistic Unfolding of abilities (linear progression) passive learner universal order of acq (all children develop in same way) Cognitive non-linear development acti ve learner individual differences Theories of Phonological Acquisition

  10. Universalist-Linguistic learning to pronounce is lower level skill-> developmental sequence related to/constrained by anatomical/physio characteristics of human auditory/artic tracts phonemes and individual sounds are the units of acquisition Cognitive acquisition of phono is cognitive process in the way child: a. forms categories b. recognizes patterns c. forms rules processes of acquis selectivity creativity hypothesis formation Theories of Phonological Acquisition

  11. Process of Acquisition whole-word acquisition (unanalyzed) recognizes similarities b/w classes of sounds and constructs rules for relating similar sounds and formulate rules develops a rule and applies it to other related items Evidence progressive idioms experimentation hypothesis formation Summary of Cognitive Model of Phonological Acquisition

  12. Process of Acquisition Child’s categories not necessarily same as adult’s Recognizes new and relevant information Creates new rules Evidence Overgeneralization/ Regression Changes Hypotheses Hypothesis Formation Summary of Cognitive Model of Phonological Acquisition

  13. 3 Components of Early Phonological Development (Stoel-Gammon, 1991) • General Patterns of Development • at 24 mo, generally have expressive vocab of ~ 300 words • ~ 50% of what they say is understood by strangers • by 3 yrs, 75% intelligibile with vocal of ~ 1000 wds and MLU of 3.1

  14. 3 Components (continued) • Individual Differences • Lot of variation among 2 year olds, but certain commonalities: • final inventory never greater than initial inventory • tendency for stops, nasals, glides before frics, liquids, affrics • front consonants appear before back consonants

  15. 3 Components (continued) • Atypical Development / RED FLAGS • numerous vowel errors • frequent initial consonant deletion • substitution of glottal stop of [h] for various consonants • deletion of final consonants at 3 years

  16. Differences in Assessing Early vs Later Linguistic Behaviors (Stoel-Gammon, 1991) • Given the tremendous individual variation in early development (babbling ->first words->word combinations), MUST use broad evaluations rather than focus on indidividual phonemes • Normal development at this age can’t be determined by comparing child’s performance with set of norms like those used for older children

  17. Stoel-Gammon (1991) Continued • Must include size and nature of phonetic inventory, correct productions, error types, and overall intelligibility (INDEPENDENT + RELATIONAL ANALYSES) • ALSO: • age of onset of meaningful speech • lexicon size

  18. Two Types of Analyses Used in Assessing Younger Children • Independent Analysis • focuses on the sound types and syllable structures produced by the child independent of the adult target • phonetic inventory (by WI/WF positions) • syllable structure • Relational Analysis • compares child’s pronunciation of word with adult form and identifies what is correct/ incorrect in relation to adult target • PCC • error patterns (phonological processes)

  19. Profile of Typical 2 Year Old (Stoel-Gammon, 1987) • Syllable Structure • Simple structure • CV, CVC, CVCV, CVCVC • Few or no clusters • only WF

  20. Profile (continued) • Phonetic Inventory • Word-Initial Inventory • 9-10 different sounds • stops, nasals, frics, glides • Word-Final Inventory • 5-6 different sounds • primarily stops with some nasals, frics, liquids

  21. Profile (continued) • Accuracy • about 70% accuracy • this suggests that children kept their vocabulary IN their phonology

  22. Who are “Late Talkers”? • At 24 months, child has < 50 word vocabulary; AND/OR • phonetic inventory with only 4-5 consonants and limited variety of vowels

  23. Phonetic Profiles of Toddlers with SLI-E (Rescorla & Ratner, 1996) • Variables that distinguished SLI-E children from TD children at 24-31 months included: • vocalization rate • SLI-E vocalized less • potentially perpetuate exp lang delay by losing opportunities for vocal practice • size of consonant inventory • SLI-E had restricted inventories (b,d, nasals, glides, h) • syllable shape preferences • SLI-E used V and CV shapes primarily

  24. Rescorla & Ratner Conclusions • Results suggest that non-grammatical (I.e., phonetic) factors contribute to the development of expressive language deficits in toddlers • Suggest a bidirectional association between child vocalization and maternal interaction • limited phonetic capacity interacts with caregivers’ interactions in a way that further reduces opportunities for exp lang learning and practice

  25. A Prospective Longitudinal Study of Phonological Development in Late Talkers (Williams & Elbert, 2003) • Independent Analyses • Phonetic Inventory (WI/WF) • Syllable Structure • Preferences (frequency of occurrence) TOKEN • Complexity (clusters) • Diversity (# different syllable structures) TYPE

  26. Williams & Elbert (continued) • Relational Analyses • PCC • Sound Variability (stability of sound system) • # diff cons attempted/# diff cons produced • no variability = 1.0 • one-to-many correspondence (phoneme collapse) = > 1.0 • many-to-one correspondence (free variation) = < 1.0 • Error Patterns • MLU and Lexicon Size

  27. Delay Larger inventories 13-15 WI; 8-11 WF (at 32 months) Greater syll diversity 9.2 different syllables at 22-33 mo More complex syll 5.4 complex syllables at 22-33 months Deviance Limited inventories 6-9 WI; 1-5 WF (at 32 months) Limited syll diversity 7.5 different syllables at 30-41 mo Simple syll structures 1.1 complex syllables at 30-41 months Phonological Delay Vs Phonological Deviance (Williams & Elbert, 2001)

  28. Delay Higher PCC (.56) at 31-33 months Lower variability (1.2) at 31-33 months Typical errors Fast rate of resolution Deviance Lower PCC (.34) at 40-41 months Greater variability (1.74) at 40-41 months Atypical errors Slow or no resolution Phonological Delay Vs Phonological Deviance (Williams & Elbert, 2001)

  29. Conclusions (Williams & Elbert, 2003) • Quantitative aspects of phonological and language skills (inventory size, lexicon size, MLU) were NOT diagnostic markers for identifying DELAYED vs DEVIANT • Instead, qualitative differences (greater variability and unusual sound errors) were identified markers of long-term delay • However, the extent of the delay was greater for the kids who did not catch up

  30. Develop a Protocol for Assessing Early Linguistic Behaviors of Late Talkers • How would you elicit the sample? • How would you analyze the sample? • Complete Analysis on Nicholas • Go beyond analysis to synthesis/summary -> what is significant? • Diagnosis • Normal Vs Delayed Vs Deviant? • Compare results to Stoel-Gammon • a. Profile of typical 2 year old • b. Red flags • Compare results to Williams & Elbert’s Red Flags