Phonological DevelopmentPhonological Development

Ages and StagesAges and Stages

Discussion OutlineDiscussion Outline

Normal Developmental StagesNormal Developmental Stages Developmental NormsDevelopmental Norms

• segmental norms vs phonological processessegmental norms vs phonological processes Theories of Phonological AcquisitionTheories of Phonological Acquisition

• Cognitive Model of Phonological AcquisitionCognitive Model of Phonological Acquisition Components of Early Phonological Components of Early Phonological

DevelopmentDevelopment Differences in Assessing Early vs Later Differences in Assessing Early vs Later

Phonological AbilitiesPhonological Abilities

Discussion Outline Discussion Outline (continued)(continued)

Types of AnalysesTypes of Analyses• Independent + RelationalIndependent + Relational

Profile of Typical 2 year oldProfile of Typical 2 year old Who are Late Talkers?Who are Late Talkers? Profiles of “Late Talkers”Profiles of “Late Talkers”

• Rescorla & RatnerRescorla & Ratner• Williams & ElbertWilliams & Elbert

Develop a Protocol for Late TalkersDevelop a Protocol for Late Talkers

4 Stages of 4 Stages of DevelopmentDevelopment

1. Prelinguistic (0 - 1 year)1. Prelinguistic (0 - 1 year)• reflexive vocalizationsreflexive vocalizations• cooingcooing• vocal playvocal play• babblingbabbling• variegated babblingvariegated babbling

2. First Words (1 - 2. First Words (1 - 1.6)1.6)

Whole-word strategyWhole-word strategy Unanalyzed “wholes”Unanalyzed “wholes” Progressive idiomsProgressive idioms

3. Phonemic 3. Phonemic Development (1.6 - 4)Development (1.6 - 4)

Rule-governed strategyRule-governed strategy 50 word vocabulary50 word vocabulary

4. Stabilization4. Stabilization Acquisition of later soundsAcquisition of later sounds

Developmental Developmental NormsNorms

Segmental acquisition studiesSegmental acquisition studies Phonological process normsPhonological process norms

Theories of Phonological Theories of Phonological AcquisitionAcquisition

Universalist-Universalist-LinguisticLinguistic• Unfolding of Unfolding of

abilities (linear abilities (linear progression)progression)

• passive learnerpassive learner• universal order of universal order of

acq (all children acq (all children develop in same develop in same way)way)

CognitiveCognitive• non-linear non-linear

developmentdevelopment• acti ve learneracti ve learner• individual individual

differencesdifferences

Theories of Phonological Theories of Phonological AcquisitionAcquisition

Universalist-LinguisticUniversalist-Linguistic• learning to pronounce learning to pronounce

is lower level skill-> is lower level skill-> developmental developmental sequencesequence– related to/constrained related to/constrained

by anatomical/physio by anatomical/physio characteristics of characteristics of human auditory/artic human auditory/artic tractstracts

• phonemes and phonemes and individual sounds are individual sounds are the units of acquisitionthe units of acquisition

CognitiveCognitive• acquisition of phono is acquisition of phono is

cognitive process in cognitive process in the way child:the way child:– a. forms categoriesa. forms categories– b. recognizes patternsb. recognizes patterns– c. forms rulesc. forms rules

• processes of acquisprocesses of acquis– selectivityselectivity– creativitycreativity– hypothesis formationhypothesis formation

Summary of Cognitive Summary of Cognitive Model of Phonological Model of Phonological AcquisitionAcquisition

Process of AcquisitionProcess of Acquisition• whole-word acquisition whole-word acquisition

(unanalyzed)(unanalyzed)

• recognizes similarities b/w recognizes similarities b/w classes of sounds and classes of sounds and constructs rules for constructs rules for relating similar sounds and relating similar sounds and formulate rulesformulate rules

• develops a rule and develops a rule and applies it to other related applies it to other related itemsitems

EvidenceEvidence• progressive idiomsprogressive idioms

• experimentationexperimentation

• hypothesis hypothesis formationformation

Summary of Cognitive Summary of Cognitive Model of Phonological Model of Phonological AcquisitionAcquisition

Process of Process of AcquisitionAcquisition• Child’s categories not Child’s categories not

necessarily same as necessarily same as adult’sadult’s

• Recognizes new and Recognizes new and relevant informationrelevant information

• Creates new rulesCreates new rules

EvidenceEvidence• OvergeneralizatioOvergeneralizatio

n/ Regressionn/ Regression

• Changes Changes HypothesesHypotheses

• Hypothesis Hypothesis FormationFormation

3 Components of Early 3 Components of Early Phonological Development Phonological Development (Stoel-Gammon, 1991)(Stoel-Gammon, 1991)

General Patterns of General Patterns of DevelopmentDevelopment• at 24 mo, generally at 24 mo, generally

have expressive vocab have expressive vocab of ~ 300 wordsof ~ 300 words

• ~ 50% of what they ~ 50% of what they say is understood by say is understood by strangersstrangers

• by 3 yrs, 75% by 3 yrs, 75% intelligibile with vocal intelligibile with vocal of ~ 1000 wds and of ~ 1000 wds and MLU of 3.1MLU of 3.1

3 Components (continued)3 Components (continued)

Individual DifferencesIndividual Differences• Lot of variation among Lot of variation among

2 year olds, but certain 2 year olds, but certain commonalities:commonalities:– final inventory never final inventory never

greater than initial greater than initial inventoryinventory

– tendency for stops, tendency for stops, nasals, glides before nasals, glides before frics, liquids, affricsfrics, liquids, affrics

– front consonants appear front consonants appear before back consonantsbefore back consonants

3 Components (continued)3 Components (continued)

Atypical Atypical Development / RED Development / RED FLAGSFLAGS• numerous vowel numerous vowel

errorserrors• frequent initial frequent initial

consonant deletionconsonant deletion• substitution of glottal substitution of glottal

stop of [h] for various stop of [h] for various consonantsconsonants

• deletion of final deletion of final consonants at 3 yearsconsonants at 3 years

Differences in Assessing Early vs Differences in Assessing Early vs Later Linguistic Behaviors (Stoel-Later Linguistic Behaviors (Stoel-Gammon, 1991)Gammon, 1991)

Given the tremendous individual Given the tremendous individual variation in early development (babbling variation in early development (babbling ->first words->word combinations), ->first words->word combinations), MUST use broad evaluations rather than MUST use broad evaluations rather than focus on indidividual phonemesfocus on indidividual phonemes

Normal development at this age can’t Normal development at this age can’t be determined by comparing child’s be determined by comparing child’s performance with set of norms like performance with set of norms like those used for older childrenthose used for older children

Stoel-Gammon (1991) Stoel-Gammon (1991) ContinuedContinued

Must include size and nature of Must include size and nature of phonetic inventory, correct phonetic inventory, correct productions, error types, and overall productions, error types, and overall intelligibility (INDEPENDENT + intelligibility (INDEPENDENT + RELATIONAL ANALYSES)RELATIONAL ANALYSES)

ALSO:ALSO:• age of onset of meaningful speechage of onset of meaningful speech• lexicon sizelexicon size

Two Types of Analyses Two Types of Analyses Used in Assessing Younger Used in Assessing Younger ChildrenChildren

Independent AnalysisIndependent Analysis• focuses on the sound types and syllable structures focuses on the sound types and syllable structures

produced by the child produced by the child independentindependent of the adult of the adult targettarget– phonetic inventory (by WI/WF positions)phonetic inventory (by WI/WF positions)– syllable structuresyllable structure

Relational AnalysisRelational Analysis• compares child’s pronunciation of word with adult compares child’s pronunciation of word with adult

form and identifies what is correct/ incorrect form and identifies what is correct/ incorrect in in relation relation to adult target to adult target– PCCPCC– error patterns (phonological processes)error patterns (phonological processes)

Profile of Typical 2 Year Profile of Typical 2 Year Old (Stoel-Gammon, 1987)Old (Stoel-Gammon, 1987)

Syllable StructureSyllable Structure• Simple structureSimple structure

– CV, CVC, CVCV, CV, CVC, CVCV, CVCVCCVCVC

• Few or no clustersFew or no clusters

– only WFonly WF

Profile (continued)Profile (continued)

Phonetic InventoryPhonetic Inventory• Word-Initial Word-Initial

InventoryInventory– 9-10 different sounds9-10 different sounds– stops, nasals, frics, stops, nasals, frics,

glidesglides

• Word-Final InventoryWord-Final Inventory– 5-6 different sounds5-6 different sounds– primarily stops with primarily stops with

some nasals, frics, some nasals, frics, liquidsliquids

Profile (continued)Profile (continued)

AccuracyAccuracy

• about 70% about 70% accuracyaccuracy

• this suggests that this suggests that children kept their children kept their vocabulary IN vocabulary IN their phonologytheir phonology

Who are “Late Talkers”?Who are “Late Talkers”?

At 24 months, child At 24 months, child has < 50 word has < 50 word vocabulary; vocabulary; AND/ORAND/OR

phonetic inventory phonetic inventory with only 4-5 with only 4-5 consonants and consonants and limited variety of limited variety of vowelsvowels

Phonetic Profiles of Toddlers Phonetic Profiles of Toddlers with SLI-E (Rescorla & with SLI-E (Rescorla & Ratner, 1996)Ratner, 1996)

Variables that distinguished SLI-E children from TD Variables that distinguished SLI-E children from TD children at 24-31 months included:children at 24-31 months included:• vocalization ratevocalization rate

– SLI-E vocalized lessSLI-E vocalized less– potentially perpetuate exp lang delay by potentially perpetuate exp lang delay by

losing opportunities for vocal practicelosing opportunities for vocal practice• size of consonant inventorysize of consonant inventory

– SLI-E had restricted inventories (b,d, nasals, SLI-E had restricted inventories (b,d, nasals, glides, h)glides, h)

• syllable shape preferencessyllable shape preferences– SLI-E used V and CV shapes primarilySLI-E used V and CV shapes primarily

Rescorla & Ratner Rescorla & Ratner ConclusionsConclusions

Results suggest that non-grammatical (I.e., Results suggest that non-grammatical (I.e., phonetic) factors contribute to the development phonetic) factors contribute to the development of expressive language deficits in toddlersof expressive language deficits in toddlers

Suggest a bidirectional association between Suggest a bidirectional association between child vocalization and maternal interactionchild vocalization and maternal interaction• limited phonetic capacity interacts with limited phonetic capacity interacts with

caregivers’ interactions in a way that further caregivers’ interactions in a way that further reduces opportunities for exp lang learning reduces opportunities for exp lang learning and practiceand practice

A Prospective Longitudinal Study of A Prospective Longitudinal Study of Phonological Development in Late Phonological Development in Late Talkers (Williams & Elbert, 2003)Talkers (Williams & Elbert, 2003)

Independent AnalysesIndependent Analyses

• Phonetic Inventory (WI/WF)Phonetic Inventory (WI/WF)

• Syllable StructureSyllable Structure– Preferences (frequency of occurrence) TOKENPreferences (frequency of occurrence) TOKEN– Complexity (clusters)Complexity (clusters)– Diversity (# different syllable structures) TYPEDiversity (# different syllable structures) TYPE

Williams & Elbert Williams & Elbert (continued)(continued)

Relational AnalysesRelational Analyses• PCCPCC• Sound Variability (stability of sound system)Sound Variability (stability of sound system)

– # diff cons attempted/# diff cons produced# diff cons attempted/# diff cons produced– no variability = 1.0no variability = 1.0– one-to-many correspondence (phoneme collapse) = > one-to-many correspondence (phoneme collapse) = >

1.01.0– many-to-one correspondence (free variation) = < 1.0many-to-one correspondence (free variation) = < 1.0

• Error PatternsError Patterns• MLU and Lexicon SizeMLU and Lexicon Size

Phonological Delay Vs Phonological Delay Vs Phonological Deviance Phonological Deviance (Williams & Elbert, 2001)(Williams & Elbert, 2001)

DelayDelay• Larger inventoriesLarger inventories

– 13-15 WI; 8-11 WF 13-15 WI; 8-11 WF (at 32 months)(at 32 months)

• Greater syll diversityGreater syll diversity– 9.2 different syllables 9.2 different syllables

at 22-33 moat 22-33 mo

• More complex syllMore complex syll– 5.4 complex syllables 5.4 complex syllables

at 22-33 monthsat 22-33 months

DevianceDeviance• Limited inventoriesLimited inventories

– 6-9 WI; 1-5 WF (at 32 6-9 WI; 1-5 WF (at 32 months)months)

• Limited syll diversityLimited syll diversity– 7.5 different syllables 7.5 different syllables

at 30-41 moat 30-41 mo

• Simple syll structuresSimple syll structures– 1.1 complex syllables 1.1 complex syllables

at 30-41 monthsat 30-41 months

Phonological Delay Vs Phonological Delay Vs Phonological Deviance Phonological Deviance (Williams & Elbert, 2001)(Williams & Elbert, 2001)

DelayDelay• Higher PCC (.56) at Higher PCC (.56) at

31-33 months31-33 months

• Lower variability Lower variability (1.2) at 31-33 (1.2) at 31-33 monthsmonths

• Typical errorsTypical errors

• Fast rate of Fast rate of resolutionresolution

DevianceDeviance• Lower PCC (.34) at Lower PCC (.34) at

40-41 months40-41 months

• Greater variability Greater variability (1.74) at 40-41 (1.74) at 40-41 monthsmonths

• Atypical errorsAtypical errors

• Slow or no resolutionSlow or no resolution

Conclusions (Williams & Conclusions (Williams & Elbert, 2003)Elbert, 2003)

Quantitative aspects of phonological and Quantitative aspects of phonological and language skills (inventory size, lexicon language skills (inventory size, lexicon size, MLU) were NOT diagnostic markers size, MLU) were NOT diagnostic markers for identifying DELAYED vs DEVIANTfor identifying DELAYED vs DEVIANT

Instead, qualitative differences (greater Instead, qualitative differences (greater variability and unusual sound errors) variability and unusual sound errors) were identified markers of long-term were identified markers of long-term delaydelay• However, the extent of the delay was greater However, the extent of the delay was greater

for the kids who did not catch upfor the kids who did not catch up

Develop a Protocol for Assessing Develop a Protocol for Assessing Early Linguistic Behaviors of Early Linguistic Behaviors of Late TalkersLate Talkers

How would you How would you elicitelicit the sample? the sample? How would you How would you analyze analyze the sample?the sample? Complete Analysis on NicholasComplete Analysis on Nicholas

• Go beyond analysis to Go beyond analysis to synthesis/summary -> synthesis/summary -> what what is significant?is significant?

DiagnosisDiagnosis• Normal Vs Delayed Vs Deviant?Normal Vs Delayed Vs Deviant?• Compare results to Stoel-GammonCompare results to Stoel-Gammon

– a. Profile of typical 2 year olda. Profile of typical 2 year old– b. Red flagsb. Red flags

• Compare results to Williams & Elbert’s Red FlagsCompare results to Williams & Elbert’s Red Flags