Non-word repetition in 2-year-olds: Replication of an adapted paradigm and a useful methodological extension

Social and Linguistic Correlates of Vocabulary Size in Autism: Overlapping Vocalization and Phonological Memory

This study sought to understand the wide variability in vocabulary development among autistic children by testing potential social and linguistic correlates of vocabulary size. The correlation between overlapping vocalization (i.e., an aspect of social interaction relevant to accessing input for vocabulary acquisition) and phonological memory (i.e., retaining linguistic sound sequences) with vocabulary size were examined in 22 autistic children (3 to 11 years old) engaged in a structured nonword repetition task. Overlapping vocalization and phonological memory were correlated with vocabulary size. Overlapping vocalization remained a significant predictor of receptive and expressive vocabulary size when controlling phonological memory and nonverbal cognition. Both social and linguistic factors were associated with receptive and expressive vocabulary size in autistic children engaged in a structured task.

Non-word repetition in Persian learning toddlers with typical development

In the current research, non-word repetition (NWR) skills of Persian learning toddlers and its association with phonological accuracy and language measures, such as percentage consonant correct (PCC), mean length utterance (MLU), and expressive vocabulary was evaluated. First, the Persian task of NWR, comprising 15 non-words, was developed and validated. Forty-four typically developing Persian learning toddlers aged from 24 to 30 months were recruited in this project. Word and NWR responses were elicited during play. MLU was investigated using serial picture description. Furthermore, the Persian version of MacArthur-Bates communicative development inventories was completed by participants' parents. The association between NWR, word repetition, MLU, and vocabulary indices was measured. Excellent values were obtained for test-retest reliability, PCC of NWR (ICC = .94, 95% CI, .78-.94, p < .001) and PCC of word repetition (ICC = .96, 95%CI, .83-.96, p < .001). The values of PCC for NWR and PCC of word repetition were 80.32 ± 13.44 and 83.51 ± 9.91, respectively. The Wilcoxon ranked test showed that participants had better performance in word repetition than NWR (z = -.275, p = .02). Significant associations were found between NWR, word repetition, MLU, number of different words, number of total words, and the expressive vocabulary size. Sex, socioeconomic status, and age did not affect NWR in this study. The findings of the current research demonstrated that the Persian task of NWR is a valid and reliable test to measure the NWR and the scores of participants were substantially associated with phonological accuracy, MLU, and vocabulary measures.

Acoustic-Lexical Characteristics of Child-Directed Speech Between 7 and 24 Months and Their Impact on Toddlers' Phonological Processing

Speech-language input from adult caregivers is a strong predictor of children's developmental outcomes. But the properties of this child-directed speech are not static over the first months or years of a child's life. This study assesses a large cohort of children and caregivers (n = 84) at 7, 10, 18, and 24 months to document (1) how a battery of phonetic, phonological, and lexical characteristics of child-directed speech changes in the first 2 years of life and (2) how input at these different stages predicts toddlers' phonological processing and vocabulary size at 2 years. Results show that most measures of child-directed speech do change as children age, and certain characteristics, like hyperarticulation, actually peak at 24 months. For language outcomes, children's phonological processing benefited from exposure to longer (in phonemes) words, more diverse word types, and enhanced coarticulation in their input. It is proposed that longer words in the input may stimulate children's phonological working memory development, while heightened coarticulation simultaneously introduces important sublexical cues and exposes them to challenging, naturalistic speech, leading to overall stronger phonological processing outcomes.

An Error Analysis of Nonword Repetition Performance in Toddlers and Young Children: Theoretical Implications and Clinical Utility

Purpose Nonword repetition has been cited as a measure of phonological working memory and continues to gain status as a clinical tool used to identify language impairment in school-age children. Less is known about nonword repetition skills in the toddler population. Method The current study presents a detailed analysis of errors by segmenting nonwords into word, syllable, and phoneme levels. Errors were also analyzed for type (e.g., addition, substitution, deletion). The Test of Early Nonword Repetition was used to measure performance in a sample of 36 typically developing children, aged 24-48 months. Clinical assessments including parent report, language sampling procedures, and standardized assessments were also administered. Results As a group, participants produced significantly more syllable errors compared to word-level errors; however, most errors were made at the phoneme level. Errors of addition were the least common error type, and no differences between substitutions or deletions were present for the entire sample. Toddlers (aged 2 years) produced more syllable-level errors compared to older children (aged 3 years). Substitution errors were positively correlated with performance on clinical measures of language, whereas deletion errors were negatively correlated with performance. Conclusion Nonword repetition performance patterns in young children may be associated with language delay or language impairment and have both clinical and theoretical relevance.

The Monosyllable Imitation Test for Toddlers: influence of stimulus characteristics on imitation, compliance and diagnostic accuracy

BACKGROUND

Although verbal imitation can provide a valuable window into the developing language abilities of toddlers, some toddlers find verbal imitation challenging and will not comply with tests that involve elicited verbal imitation. The characteristics of stimuli that are offered to toddlers for imitation may influence how easy or hard it is for them to imitate. This study presents a new test of elicited imitation-the Monosyllable Imitation Test for Toddlers (MITT)-comprising stimuli of varying characteristics and test features designed to optimize compliance.

AIMS

To investigate whether the stimulus characteristics of neighbourhood density and consonant complexity have independent and/or convergent influences on imitation accuracy; and to examine non-compliance rates and diagnostic accuracy of the MITT and an existing test, the Test of Early Nonword Repetition (TENR) (Stokes and Klee 2009a).

METHODS & PROCEDURES

Fifty-two toddlers (25-35 months) participated. Twenty-six had typically developing language (TDs) and 26 were defined as late talkers (LTs) based on parent-reported vocabulary. The MITT stimuli were created by manipulating both neighbourhood density (dense or sparse) and consonant complexity (early- or late-developing initial consonant). The MITT was designed to maximize compliance by: (1) using eight monosyllabic stimuli, (2) providing three exposures to stimuli and (3) embedding imitation in a motivating context: a computer animation with reasons for imitation.

OUTCOMES & RESULTS

Stimulus characteristics influenced imitation accuracy in TDs and LTs. For TDs, neighbourhood density had an independent influence, whereas for LTs consonant complexity had an independent influence. These characteristics also had convergent influences. For TDs, stimuli were all equally easy to imitate, except those that were both sparse and contained a late-developing consonant which were harder to imitate. For LTs, stimuli that were both dense and contained an early-developing consonant were easier to imitate than any other stimuli. Two LTs and no TDs were non-compliant with the MITT. With the TENR, five LTs and two TDs were non-compliant. The MITT and TENR yielded similar levels of diagnostic sensitivity, but the TENR offered higher specificity rates. Subsets of stimuli from the MITT and the TENR also showed diagnostic promise when explored post-hoc.

CONCLUSIONS & IMPLICATIONS

Stimulus characteristics converge to influence imitation accuracy in both TD and LT toddlers and therefore should be considered when designing stimuli. The MITT resulted in better compliance than the TENR, but the TENR offered higher specificity. Insights about late talking, elicited imitation and speech production capabilities are discussed.

Phonological memory in young children who stutter

This study investigated phonological memory in 5- and 6-year old children who stutter. Participants were 11 children who stutter matched on general language abilities, maternal education level, and sex to 11 typically fluent children. Participants completed norm-referenced nonword repetition and digit span tasks, as well as measures of expressive and receptive vocabulary and articulation. The nonword repetition task included stimuli that ranged from 1 to 7 syllables, while the digit naming task contained number strings containing 2-10 digits. Standardized tests of vocabulary and articulation abilities were tested as well. Groups were comparable on measures expressive vocabulary, receptive vocabulary, and articulation. Despite the fact that the majority of participants scored within typical limits, young children who stutter still performed significantly less well than children who do not stutter on the nonword repetition task. No between-group differences were revealed in the digit naming task. Typically fluent children demonstrated strong correlations between phonological memory tasks and language measures, while children who stutter did not. These findings indicate that young children who stutter may have sub-clinical differences in nonword repetition.