Intelligibility in Context Scale: Growth Curves for Typically Developing English-Speaking Children Between Ages 2;6 and 9;11.

PURPOSE: The aim of this study was to quantify the clinical utility of the Intelligibility in Context Scale (ICS) English version by characterizing the growth patterns of the ICS composite scores and seven ICS individual item scores of typically developing American English-speaking children. METHOD: Parents of 545 typically developing children aged 2;6-9;11 (years;months) completed the ICS. Using a proportional odds model, we regressed ICS composite scores on age and computed for model-estimated mean and lower quantile ICS composite scores. Logistic regression and proportional odds modeling were utilized to quantify the relationship of individual ICS items and age. RESULTS: ICS composite scores of typically developing children changed with age, but change was small and incremental, with scores compressed between 3 and 5 across the range of ages. An average child (i.e., on the 50th percentile) is expected to have an ICS composite score of 4 beginning at 3;0 and an ICS composite score of 5 by 6;6. On average, parents gave different intelligibility ratings based on communicative partners, and the rating differences between communicative partners decreased with age. CONCLUSIONS: Given that ICS scores increase with age, the expected score for average children also increases. A child's age is a main factor for interpreting ICS scores.

Preschoolers rely on rich speech representations to process variable speech.

To learn language, children must map variable input to categories such as phones and words. How do children process variation and distinguish between variable pronunciations ("shoup" for soup) versus new words? The unique sensory experience of children with cochlear implants, who learn speech through their device's degraded signal, lends new insight into this question. In a mispronunciation sensitivity eyetracking task, children with implants (N = 33), and typical hearing (N = 24; 36-66 months; 36F, 19M; all non-Hispanic white), with larger vocabularies processed known words faster. But children with implants were less sensitive to mispronunciations than typical hearing controls. Thus, children of all hearing experiences use lexical knowledge to process familiar words but require detailed speech representations to process variable speech in real time.

Developmental Cut-Points for Atypical Speech Intelligibility in Children With Cerebral Palsy.

PURPOSE: Early identification of speech motor involvement (SMI) in children with cerebral palsy (CP) is difficult because of overlapping features with many aspects of typical speech development. Quantitative measures of speech intelligibility have the potential to differentiate between children with SMI and those with no SMI (NSMI). We examined thresholds for speech intelligibility development in children with CP relative to the low end of age-specific typical developmental expectations. We sought to determine whether there were intelligibility differences between children with CP and NSMI versus typically developing (TD) age-mates across the range of development and whether there were differences between children with CP who have NSMI and those with CP who have SMI across the range of development based on speech intelligibility. METHOD: We used two large existing data sets that included speech samples from children between the ages of 2.5 and 8 years. One data set included 511 longitudinal speech samples from children with CP; the other included 505 cross-sectional speech samples from TD children. We examined receiver operating characteristic curves and sensitivity/specificity results by age for differentiating among groups of children. RESULTS: TD children versus those with CP and NSMI showed differentiation in their speech intelligibility across all ages, but the strength of differentiation was only marginally above chance. Children with CP and NSMI showed clear differentiation in their speech intelligibility from those with CP and SMI beginning at the earliest age point. Children with CP who have intelligibility below 40% at the age of 3 years have a very high probability of having SMI. CONCLUSIONS: Early intelligibility screening should be performed in children diagnosed with CP. Those with intelligibility below 40% at 3 years of age should be referred immediately for speech assessment and treatment.

Lexical Predictors of Intelligibility in Young Children's Speech.

PURPOSE: Speech perception is a probabilistic process, integrating bottom-up and top-down sources of information, and the frequency and phonological neighborhood of a word can predict how well it is perceived. In addition to asking how intelligible speakers are, it is important to ask how intelligible individual words are. We examined whether lexical features of words influenced intelligibility in young children. In particular, we applied the neighborhood activation model, which posits that a word's frequency and the overall frequency of a word's phonological competitors jointly affect the intelligibility of a word. METHOD: We measured the intelligibility of 165 children between 30 and 47 months in age on 38 different single words. We performed an item response analysis using generalized mixed-effects logistic regression, adding word-level characteristics (target frequency, neighborhood competition, motor complexity, and phonotactic probability) as predictors of intelligibility. RESULTS: There was considerable variation among the words and the children, but between-word variability was larger in magnitude than between-child variability. There was a clear positive effect of target word frequency and a negative effect of neighborhood competition. We did not find a clear negative effect of motor complexity, and phonotactic probability did not have any effect on intelligibility. CONCLUSION: Word frequency and neighborhood competition both had an effect on intelligibility in young children's speech, so listener expectations are an important factor in the selection of items for children's intelligibility assessment.

Perceptual measurement of articulatory goodness in young children: Relationships with age, speech sound acquisition, and intelligibility.

Speech language pathologists regularly use perceptual methods in clinical practice to assess children's speech. In this study, we examined relationships between measures of speech intelligibility, clinical articulation test results, age, and perceptual ratings of articulatory goodness for children. We also examined the extent to which established measures of intelligibility and clinical articulation test results predicted articulatory goodness ratings, and whether goodness ratings were influenced by intelligibility. A sample of 164 (30-47 months) typically developing children provided speech samples and completed a standardised articulation test. Single word intelligibility scores and ratings of articulatory goodness were gathered from 328 naïve listeners; scores on a standardised articulation test were obtained from each child. Bivariate Pearson correlation, linear regression, and linear mixed effects modelling were used for analysis. Results showed that articulatory goodness ratings had the highest correlation with intelligibility, followed by age, followed by articulation score. Age and clinical articulation scores were both significant predictors of goodness ratings, but articulation scores made only a small contribution to prediction. Articulatory goodness ratings were substantially lower for unintelligible words compared to intelligible words, but articulatory goodness scores increased with age at the same rate for unintelligible and intelligible words. Perceptual ratings of articulatory goodness are sensitive to developmental changes in speech production (regardless of intelligibility) and yield a different kind of information than clinical articulation scores from standardised measures.

Longitudinal change in speech classification between 4 and 10 years in children with cerebral palsy.

AIM: To examine speech impairment severity classification over time in a longitudinal cohort of children with cerebral palsy (CP). METHOD: A total of 101 children (58 males, 43 females) between the ages of 4 and 10 years with CP participated in this longitudinal study. Speech severity was rated using the Viking Speech Scale (VSS), a four-level classification rating scale, at 4, 6, 8, and 10 years (age 4 years: mean = 52 months [3 SD]; age 6 years: mean = 75 months [2 SD]; age 8 years: mean = 100 months [4 SD]; age 10 years: mean = 125 months [5 SD]). We used Bayesian mixed-effects ordinal logistic regression to model (1) the extent to which speech severity changed over time and (2) patterns of change across age groups and classification rating group levels. RESULTS: VSS ratings decreased (speech severity became less severe) between 4 and 10 years of age. Children who were first classified in VSS levels I, II, or III at age 4 years had a high probability of staying at, or improving to, VSS level I by 10 years. Children who were first classified in VSS level IV at 4 years had a high probability of remaining in VSS level IV at 10 years. INTERPRETATION: Early speech performance is highly predictive of later childhood speech abilities. Children with any level of speech impairment at age 4 years should be receiving speech therapy. Those with more severe speech impairments should be introduced to augmentative and alternative communication as soon as possible. WHAT THIS PAPER ADDS: Children with early Viking Speech Scale (VSS) ratings below level IV have a good prognosis for speech improvement. Children with early VSS level IV ratings are likely to remain at VSS level IV over time. Children did not show worsening of VSS level between the ages of 4 and 10 years.

Cambio longitudinal en la clasificación del habla entre los 4 y 10 años en niños con parálisis cerebral OBJETIVO: Examinar la clasificación de la gravedad del deterioro del habla a lo largo del tiempo en una cohorte longitudinal de niños con parálisis cerebral (PC) entre las edades de 4 y 10 años. MÉTODO: Un total de 101 niños (58 varones, 43 mujeres) con PC participaron en este estudio longitudinal. La gravedad del habla se evaluó utilizando la Viking Speech Scale (VSS), una escala de calificación de clasificación de cuatro niveles, a los 4, 6, 8 y 10 años (edad 4 años: media = 52 meses [3 DE]; edad 6 años: media = 75 meses [2 DE]; edad 8 años: media = 100 meses [4 DE]; edad 10 años: media = 125 meses [5 DE]). Utilizamos la regresión logística ordinal de efectos mixtos bayesianos para modelar (1) la medida en que la severidad del habla cambió con el tiempo y (2) los patrones de cambio entre los grupos de edad y los niveles de clasificación de los grupos. RESULTADOS: Las calificaciones de VSS disminuyeron (la severidad del habla se volvió menos severa) entre los 4 y los 10 años de edad. Los niños que fueron clasificados por primera vez en los niveles I, II o III de VSS a los 4 años tenían una alta probabilidad de permanecer en el nivel I de VSS o mejorar al nivel I de VSS a los 10 años. Los niños que fueron clasificados por primera vez en el nivel IV de VSS a los 4 años tenían una alta probabilidad de permanecer en el nivel IV de VSS a los 10 años. INTERPRETACIÓN: El desempeño temprano del habla es altamente predictivo de las habilidades del habla en la niñez posterior. Los niños con cualquier nivel de discapacidad del habla a la edad de 4 años deben recibir terapia del habla. Aquellos con impedimentos del habla más severos deben ser introducidos a la comunicación aumentativa y alternativa tan pronto como sea posible.

Mudança longitudinal na classificação da fala entre 4 e 10 anos em crianças com paralisia cerebral OBJETIVO: Analisar a classificação da gravidade do comprometimento da fala ao longo do tempo em uma coorte longitudinal de crianças com paralisia cerebral (PC) entre 4 e 10 anos. MÉTODO: Um total de 101 crianças (58 meninos, 43 meninas) com PC participaram deste estudo longitudinal. A gravidade da fala foi avaliada usando a Viking Speech Scale (VSS), uma escala de classificação de quatro níveis, aos 4, 6, 8 e 10 anos (idade 4 anos: média = 52 meses [3 DP]; idade 6 anos: média = 75 meses [2 DP]; idade 8 anos: média = 100 meses [4 DP]; idade 10 anos: média = 125 meses [5 DP]). Usamos a regressão logística ordinal Bayesiana de efeitos mistos para modelar (1) a extensão em que a gravidade da fala mudou ao longo do tempo e (2) padrões de mudança entre as faixas etárias e os níveis de classificação do grupo. RESULTADOS: As classificações de VSS diminuíram (a gravidade da fala tornou-se menos grave) entre 4 e 10 anos de idade. As crianças que foram classificadas pela primeira vez nos níveis VSS I, II ou III aos 4 anos de idade tiveram uma alta probabilidade de permanecer ou melhorar para o nível VSS I em 10 anos. As crianças que foram classificadas pela primeira vez em VSS nível IV aos 4 anos tiveram alta probabilidade de permanecer no VSS nível IV aos 10 anos. INTERPRETAÇÃO: O desempenho precoce da fala é altamente preditivo de habilidades de fala na infância posteriormente. Crianças com qualquer nível de deficiência de fala aos 4 anos de idade devem receber terapia da fala. Aqueles com deficiências de fala mais graves devem ser introduzidos à comunicação aumentativa e alternativa o mais rápido possível.

Speech Development Between 30 and 119 Months in Typical Children II: Articulation Rate Growth Curves.

Purpose We aimed to develop normative growth curves for articulation rate during sentence repetition for typically developing children. Our primary goal was the development of quantile/percentile growth curves so that typical variation in articulation rate with age could be estimated. We also estimated when children became adultlike in their articulation rate, and we examined the contributions of age and utterance length to articulation rate. Method This cross-sectional study involved collection of in-person speech samples from 570 typically developing children (297 girls; 273 boys) who passed speech, language, and hearing screening measures. Pauses greater than 150 ms in duration were removed from the samples, and articulation rate was measured in syllables per second (sps). Results Articulation rate reliably increased with age and utterance length. Rate in all key percentiles increased with age. The median rate (50th percentile) increased from 2.7 sps at 36 months to 3.3 sps at 96 months. The 5th percentile increased from 2.3 to 3.1 sps over the same age range. Using 3.2 sps as a benchmark for adultlike speech, we found the 25th, 50th, and 75th percentiles reached adultlike rates at 99, 75, and 53 months, respectively. Conclusions Articulation rate increases from early childhood into middle childhood, and it is generally adultlike by 10 years of age. Variability in articulation rate among typical children was substantial. Implications for prior research and for clinical usage are discussed.

Speech Development Between 30 and 119 Months in Typical Children I: Intelligibility Growth Curves for Single-Word and Multiword Productions.

Purpose We extended our earlier study on normative growth curves for intelligibility development in typical children from 30 to 119 months of age. We also determined quantile-specific age of steepest growth and growth rates. A key goal was to establish age-specific benchmarks for single-word and multiword intelligibility. Method This cross-sectional study involved collection of in-person speech samples from 538 typically developing children (282 girls and 256 boys) who passed speech, language, and hearing screening measures. One thousand seventy-six normal-hearing naïve adult listeners (280 men and 796 women) orthographically transcribed children's speech. Speech intelligibility was measured as the percentage of words transcribed correctly by naive adults, with single-word and multiword intelligibility outcomes modeled separately. Results The age range for 50% single-word intelligibility was 31-47 months (50th-5th percentiles), the age range for 75% single-word intelligibility was 49-87 months, and the age range for 90% intelligibility for single words was 83-120+ months. The same milestones were attained for multiword intelligibility at 34-46, 46-61, and 62-87 months, respectively. The age of steepest growth for the 50th percentile was 30-31 months for both single-word and multiword intelligibility and was later for children in lower percentiles. The maximum growth rate was 1.7 intelligibility percentage points per month for single words and 2.5 intelligibility percentage points per month for multiword intelligibility. Conclusions There was considerable variability in intelligibility development among typical children. For children in median and lower percentiles, intelligibility growth continues through 9 years. Children should be at least 50% intelligible by 48 months. Supplemental Material https://doi.org/10.23641/asha.16583426.

Performance of Forced-Alignment Algorithms on Children's Speech.

Purpose Acoustic measurement of speech sounds requires first segmenting the speech signal into relevant units (words, phones, etc.). Manual segmentation is cumbersome and time consuming. Forced-alignment algorithms automate this process by aligning a transcript and a speech sample. We compared the phoneme-level alignment performance of five available forced-alignment algorithms on a corpus of child speech. Our goal was to document aligner performance for child speech researchers. Method The child speech sample included 42 children between 3 and 6 years of age. The corpus was force-aligned using the Montreal Forced Aligner with and without speaker adaptive training, triphone alignment from the Kaldi speech recognition engine, the Prosodylab-Aligner, and the Penn Phonetics Lab Forced Aligner. The sample was also manually aligned to create gold-standard alignments. We evaluated alignment algorithms in terms of accuracy (whether the interval covers the midpoint of the manual alignment) and difference in phone-onset times between the automatic and manual intervals. Results The Montreal Forced Aligner with speaker adaptive training showed the highest accuracy and smallest timing differences. Vowels were consistently the most accurately aligned class of sounds across all the aligners, and alignment accuracy increased with age for fricative sounds across the aligners too. Conclusion The best-performing aligner fell just short of human-level reliability for forced alignment. Researchers can use forced alignment with child speech for certain classes of sounds (vowels, fricatives for older children), especially as part of a semi-automated workflow where alignments are later inspected for gross errors. Supplemental Material https://doi.org/10.23641/asha.14167058.

Validity of Parent Ratings of Speech Intelligibility for Children with Cerebral Palsy.

Aim: To examine the relationship between subjective parent ratings of intelligibility and objectively measured intelligibility scores for children with cerebral palsy (CP) with differing levels of speech severity. Method: Fifty children (84-96 months) with CP were classified into groups based on intelligibility scores during a speech elicitation task - high intelligibility (90% or higher), mild-moderate intelligibility reduction (61-89%), and severe intelligibility reduction (60% or lower). Parent ratings of understandability (on a 7-point scale) were compared to intelligibility scores gathered from 100 naïve listeners. Results: For children with mild-moderate and severe intelligibility reduction, there was a large range of variability in parent ratings. For children with high intelligibility, ratings were consistent with intelligibility scores. There was a range of intelligibility scores within each rating, especially in the middle of the scale. Conclusions: For children with mild-moderate intelligibility deficits, parent ratings may best be used in conjunction with objective measurement of intelligibility.

Longitudinal Growth in Intelligibility of Connected Speech From 2 to 8 Years in Children With Cerebral Palsy: A Novel Bayesian Approach.

Aim The aim of the study was to examine longitudinal growth in intelligibility in connected speech from 2 to 8 years of age in children with cerebral palsy. Method Sixty-five children with cerebral palsy participated in the longitudinal study. Children were classified into speech-language profile groups using age-4 data: no speech motor impairment (SMI), SMI with typical language comprehension, and SMI with impaired language comprehension. We fit a Bayesian nonlinear mixed-effects model of intelligibility growth at the child and group levels. We compared groups by age of steepest growth, maximum growth rate, and predicted intelligibility at 8 years of age. Results The no SMI group showed earlier and steeper intelligibility growth and higher average outcomes compared to the SMI groups. The SMI groups had more variable growth trajectories, but the SMI with typical language comprehension group had higher age-8 outcomes and steeper rates of maximum growth than the SMI with impaired language comprehension group. Language comprehension impairment at age of 4 years predicted lower intelligibility outcomes at age of 8 years, compared to typical language at age of 4 years. Interpretation Children with SMI at age of 4 years show highly variable intelligibility growth trajectories, and comorbid language comprehension impairment predicts lower intelligibility outcomes. Supplemental Material https://doi.org/10.23641/asha.12777659.

Measuring Speech Production Development in Children With Cerebral Palsy Between 6 and 8 Years of Age: Relationships Among Measures.

Purpose Accurate measurement of speech intelligibility is essential for children with speech production deficits, but wide variability exists in the measures and protocols used. The current study sought to examine relationships among measures of speech intelligibility and the capacity of different measures to capture change over time. Method Forty-five children with cerebral palsy (CP) with and without speech motor impairment were observed at ages 6, 7, and 8 years. The speech performance of each child was rated using four measures at each time point: standardized articulation test scores, multiword intelligibility scores obtained from naïve listeners, parent ratings of intelligibility, and percent intelligible utterances obtained from language transcripts. We analyzed the correlations of measures within each age and within three different severity groups, and we analyzed how these measures changed year over year in each severity group. Results For children with CP who have mild and moderate speech deficits, different measures of speech production were weakly associated, and for children with CP with severe speech impairment, these measures showed stronger associations. The four measures also differed in their ability to capture change over time. Finally, results from standardized assessments of articulation were not found to inform overall speech intelligibility for children with mild and moderate speech deficits. Conclusions Results suggest that speech production is not fully described by any single clinical measure. In order to adequately describe functional speaking abilities and to capture change over time, multiple levels of measurement are required.

Development of Speech Intelligibility Between 30 and 47 Months in Typically Developing Children: A Cross-Sectional Study of Growth.

Purpose We sought to establish normative growth curves for intelligibility development for the speech of typically developing children as revealed by objectively based orthographic transcription of elicited single-word and multiword utterances by naïve listeners. We also examined sex differences, and we compared differences between single-word and multiword intelligibility growth. Method One hundred sixty-four typically developing children (92 girls, 72 boys) contributed speech samples for this study. Children were between the ages of 30 and 47 months, and analyses examined 1-month age increments between these ages. Two different naïve listeners heard each child and made orthographic transcriptions of child-produced words and sentences (n = 328 listeners). Average intelligibility scores for single-word productions and multiword productions were modeled using linear regression, which estimated normal-model quantile age trajectories for single- and multiword utterances. Results We present growth curves showing steady linear change over time in 1-month increments from 30 to 47 months for 5th, 10th, 25th, 50th, 75th, 90th, and 95th percentiles. Results showed that boys did not differ from girls and that, prior to 35 months of age, single words were more intelligible than multiword productions. Starting at 41 months of age, the reverse was true. Multiword intelligibility grew at a faster rate than single-word intelligibility. Conclusions Children make steady progress in intelligibility development through 47 months, and only a small number of children approach 100% intelligibility by this age. Intelligibility continues to develop past the fourth year of life. There is considerable variability among children with regard to intelligibility development. Supplemental Material https://doi.org/10.23641/asha.12330956.

Longitudinal Growth in Single-Word Intelligibility Among Children With Cerebral Palsy From 24 to 96 Months of Age: Effects of Speech-Language Profile Group Membership on Outcomes.

Purpose We examined whether there were differences among speech-language profile groups of children with cerebral palsy (CP) in age of crossing 25%, 50%, and 75% intelligibility thresholds; age of greatest intelligibility growth; rate of intelligibility growth; maximum attained intelligibility at 8 years; and how well intelligibility at 36 months predicts intelligibility at 96 months when group membership is accounted for. Profile groups were children with no speech motor impairment (NSMI), those with speech motor impairment and language comprehension that is typically developing (SMI-LCT), and those with speech motor impairment and language comprehension impairment (SMI-LCI). Method Sixty-eight children with CP were followed longitudinally between 24 and 96 months of age. A total of 564 time points were examined across children (M = 8.3 time points per child, SD = 2.6). We fitted a nonlinear random effects model for longitudinal observations, allowing for differences between profile groups. We used the fitted model trajectories to generate descriptive analyses of intelligibility growth by group and to generate simulations to analyze how well 36-month intelligibility data predicted 96-month data accounting for profile groups. Results Children with CP who have NSMI have different growth and better intelligibility outcomes than those with speech motor impairment. Children with SMI-LCT tend to have better outcomes but similar intelligibility growth as children with SMI-LCI. There may be a subset of children that cut across SMI-LCI and SMI-LCT groups who have severe speech motor involvement and show limited growth in intelligibility. Conclusions Intelligibility outcomes for children with CP are affected by profile group membership. Intelligibility growth tends to be delayed in children with speech motor impairment. Intelligibility at 3 years is highly predictive of later outcomes regardless of profile group. Intervention decision making should include consideration of early intelligibility, and treatment directions should include consideration of augmentative and alternative communication.

Comparing Automatic Eye Tracking and Manual Gaze Coding Methods in Young Children with Autism Spectrum Disorder.

Eye-gaze methods offer numerous advantages for studying cognitive processes in children with autism spectrum disorder (ASD), but data loss may threaten the validity and generalizability of results. Some eye-gaze systems may be more vulnerable to data loss than others, but to our knowledge, this issue has not been empirically investigated. In the current study, we asked whether automatic eye-tracking and manual gaze coding produce different rates of data loss or different results in a group of 51 toddlers with ASD. Data from both systems were gathered (from the same children) simultaneously, during the same experimental sessions. As predicted, manual gaze coding produced significantly less data loss than automatic eye tracking, as indicated by the number of usable trials and the proportion of looks to the images per trial. In addition, automatic eye-tracking and manual gaze coding produced different patterns of results, suggesting that the eye-gaze system used to address a particular research question could alter a study's findings and the scientific conclusions that follow. It is our hope that the information from this and future methodological studies will help researchers to select the eye-gaze measurement system that best fits their research questions and target population, as well as help consumers of autism research to interpret the findings from studies that utilize eye-gaze methods with children with ASD. Autism Res 2020, 13: 271-283. © 2019 International Society for Autism Research, Wiley Periodicals, Inc. LAY SUMMARY: The current study found that automatic eye-tracking and manual gaze coding produced different rates of data loss and different overall patterns of results in young children with ASD. These findings show that the choice of eye-gaze system may impact the findings of a study-important information for both researchers and consumers of autism research.

Effects of Rate Manipulation on Intelligibility in Children With Cerebral Palsy.

Purpose We evaluated the effects of a speech supplementation strategy to reduce rate and improve intelligibility in children with cerebral palsy. Method Twenty-five children with cerebral palsy (M age = 12.08 years) completed a structured speaking task in 2 speech conditions: habitual speech and slow speech. Fifteen children had mild intelligibility deficits; 10 had moderate-severe intelligibility deficits. In each condition, children repeated utterances of 2-7 words in length. In the habitual speech condition, children used their natural and unaltered speaking rate. In the slow speech condition, children were cued to insert pauses between words. Intelligibility ratings were obtained from orthographic transcriptions by unfamiliar adult listeners (n = 100). Speech rate, in words per minute, was measured for each utterance. Results All children, regardless of severity group, were able to reduce their rate of speech when implementing the slow speech strategy. Only children in the moderate-severe group showed an improvement in intelligibility when implementing the slow speech strategy. Although there was considerable individual variability, there was a greater improvement in intelligibility for longer utterances compared to shorter ones. Conclusion A slow speech strategy may be beneficial for children with moderate-severe intelligibility deficits who speak in longer utterances. Future studies should seek to further examine the clinical feasibility of slow speech for children with reduced intelligibility.

Using language input and lexical processing to predict vocabulary size.

Children learn words by listening to caregivers, and the quantity and quality of early language input predict later language development. Recent research suggests that word recognition efficiency may influence the relationship between input and vocabulary growth. We asked whether language input and lexical processing at 28-39 months predicted vocabulary size one year later in 109 preschoolers. Input was measured using adult word counts from LENA recordings. We used the visual world paradigm and measured lexical processing as the rate of change in proportion of looks to target. Regression analysis showed that lexical processing did not constrain the effect of input on vocabulary size. We also found that input and processing were more reliable predictors of receptive than expressive vocabulary growth.

Vocabulary size and auditory word recognition in preschool children.

Recognizing familiar words quickly and accurately facilitates learning new words, as well as other aspects of language acquisition. This study used the visual world paradigm with semantic and phonological competitors to study lexical processing efficiency in 2-5 year-old children. Experiment 1 found this paradigm was sensitive to vocabulary-size differences. Experiment 2 included a more diverse group of children who were tested in their native dialect (either African American English or Mainstream American English). No effect of stimulus dialect was observed,. Results showed that vocabulary size was a better predictor of eye gaze patterns than maternal education, but that maternal education level had a moderating effect; as maternal education level increased, vocabulary size was less predictive of lexical processing efficiency.

Anticipatory coarticulation facilitates word recognition in toddlers.

Children learn from their environments and their caregivers. To capitalize on learning opportunities, young children have to recognize familiar words efficiently by integrating contextual cues across word boundaries. Previous research has shown that adults can use phonetic cues from anticipatory coarticulation during word recognition. We asked whether 18-24 month-olds (n=29) used coarticulatory cues on the word "the" when recognizing the following noun. We performed a looking-while-listening eyetracking experiment to examine word recognition in neutral vs. facilitating coarticulatory conditions. Participants looked to the target image significantly sooner when the determiner contained facilitating coarticulatory cues. These results provide the first evidence that novice word-learners can take advantage of anticipatory sub-phonemic cues during word recognition.