Late Talkers

Determining Recovery or Persistence at an Early Age

US Preventive Services Task Force (Nelson et al., 2006)

• Examined putative risk factors (child, family, and environment)

• Systematic review of risk factors identified– Set of consistently reported factors

• Family hx of S/L delay• Male gender• Parent educational levels• Perinatal factors (twin birth, prematurity, birth weight)

– Set of less consistently reported factors• Childhood illnesses• Later birth order• Family size• Older parents or younger mother• Lower SES• Minority race

Early Language in Victoria Study (ELVS) Reilly et al. 2007

• Prospective, longitudinal study of 1,720 infants at 8 months and followed at 12 and 24 months of age

• Examined all putative risk factors identified by US Preventive Services Task Force EXCEPT child illnesses and family size

• Found that NONE of the 12 early risk factors was a strong predictor of communication and vocabulary skills in 24 month-old children

• Communication score (CSBS and CDI) at 12 months was better predictor of outcome at 24 months

Discussion Outline

• Normal Developmental Stages• Components of Early Phonological Development• Differences in Assessing Early vs Later Phonological

Abilities• Types of Analyses

– Independent + Relational

• Profile of Typical 2 year old (consider linguistic differences)

• Who are Late Talkers?• Profiles of “Late Talkers”

– Carson, Klee, Carson, & Hime (2003)– Williams & Elbert (2003)

• Develop a Protocol for Late Talkers

Processes and Evidence of Phonological Acquisition

• Process of Acquisition– whole-word acquisition

(unanalyzed)

– recognizes similarities between 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

Processes and Evidence of Phonological Acquisition

• 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

4 Stages of phonological Development

• 1. Prelinguistic (0 - 1 year)

• 2. First Words (12 – 18 months)

• 3. Phonemic Development (18 months – 4 years)

• 4. Stabilization (4 years – 8 years)

1. Prelinguistic (0 – 1 year)

• reflexive vocalizations• Cooing -2 months of age (Back sounds)• vocal play - 4 to 6 months (experiment with range of

sounds, Squeling, rasparries)• Babbling – 6months to 10months –(canonical babaling

babababab)• variegated babbling – 10months (badamadadab)

2. First Words (12 – 18 months)

• Whole-word strategy– Unanalyzed “wholes”(not stable, lots of variablity)– Variable productions due to no stable correspondence

within and across lexical items

• Progressive idioms• Active selectivity/avoidance of vocabulary that

contain sounds that are IN or OUT of phonetic repertoire (very important)

• Simple syllable structure (CV, CVC, CVCV) with primarily stops, nasals, glides produced at labial and alveolar places of production

3. Phonemic Development (18 months – 4 years)

• 50-word stage at 18 months – rapid vocabulary growth after this point

• Rule-governed strategy– Rapid increase in vocabulary size– Relationship between child’s productions and the adult target

becomes more systematic (predictable; rule-governed)

4. Stabilization (4 – 8 years)

• Stabilization of variable productions

• Acquisition of later sounds (liquids, fricatives, affricates, clusters)

Developmental Norms

• Segmental acquisition studies– Number of studies, which used different sampling

methods (imit ~ spon; IMF positions); and different criterion levels (50%, 75%, 90%)

– A small difference in methodology can result in great differences in age of acquisition reported by studies

– Developmental norms cannot account for individual differences across children that is typical in normal acquisition

• Phonological process norms– Newer way to describe phonological acquisition by

using age at which typical phonological processes are suppressed

– Some problems with this perspective

3 Components of Early Phonological Development

Stoel-Gammon, 1991)(Stoel-Gammon, 1991)

• General Patterns of Development– at 24 mo, generally have

expressive vocabulary of ~ 300 words

– ~ 50% of what they say is understood by strangers

– by 3 yrs, children are 75% intelligible with vocabulary of ~ 1000 words and MLU of 3.1

3 Components (continued)

• Individual Differences– Lot of variation among 2

year olds, but certain commonalities:

• Final phonetic inventory never greater than initial inventory(very important)

• tendency for stops, nasals, glides before frics, liquids, affricates

• front consonants appear before back consonants

3 Components (continued)

• Atypical Development / RED FLAGS– numerous vowel errors– frequent initial consonant

deletion(smaller initial inventory than final)

– substitution of glottal stop or [h] for various consonants

– deletion of final consonants at 3 years

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 individual 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

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

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) (sounds the child is

making. Does not have to be saying it corectly)

• 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 (percentage of consonant correct)• error patterns (phonological processes)

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

• Syllable Structure– Simple structure

• CV, CVC, CVCV, CVCVC

– Few or no clusters

• only WF

Profile 2 year(continued)

• Phonetic Inventory (independent)– Word-Initial Inventory

• 9-10 different sounds• stops, nasals, fricatives,

glides

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

some nasals, frics, liquids

Profile (continued)

• Accuracy (relational)

– about 70% accuracy

– this suggests that children kept their vocabulary IN their phonology

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

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

• This potentially perpetuates exp language 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

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 language learning and practice

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

• Independent Analyses– Phonetic Inventory (WI/WF)– Syllable Structure

• Relational Analyses– PCC– Sound Variability (stability of sound system)

• # diff consonants attempted/# diff cons produced

– Error Patterns– MLU and Lexicon Size

Phonological Delay Vs Deviance (Williams & Elbert, 2003)

• 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 syllables• 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 Deviance (Williams & Elbert, 2003)

• 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

Conclusions (Williams & Elbert, 2003)

• Quantitative aspects of phonological and language skills (inventory size, lexicon size, MLU) alone were NOT diagnostic markers for identifying DELAYED vs DEVIANT– However, the extent of the delay was greater for the kids who did not

catch up

• Qualitative differences (greater variability and unusual sound errors) were also identified markers of long-term delay

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 late talker

– Go beyond analysis to synthesis/summary -> what is significant? (assignment instuctions)

• 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

PEEPS™ (Williams & Stoel-Gammon, in progress)

PEEPS™

• Designed to assess early phonological skills in 18-36 month old children

• Includes 60 items elicited through manipulatives (39 items) or naming body parts and clothing on doll (21 items)

• Divided into two word lists– Basic Word List (12-24 mo): 40 words– Expanded Word List (24-36 mo): 20 words

• Analysis Forms (Relational & Independent)• Profiles of Typical Development (18, 24, 30, 36 mo)