A developmental account of the role of sequential dependencies in typical and atypical language learners.

The Gerken lab has shown that infants are able to learn sound patterns that obligate local sequential dependencies that are no longer readily accessible to adults. The Goffman lab has shown that children with developmental language disorder (DLD) exhibit deficits in learning sequential dependencies that influence the acquisition of words and grammar, as well as other types of domain general sequences. Thus, DLD appears to be an impaired ability to detect and deploy sequential dependencies over multiple domains. We meld these two lines of research to propose a novel account in which sequential dependency learning is required for many phonological and morphosyntactic patterns in natural language and is also central to the language and domain general deficits that are attested in DLD. However, patterns that are not dependent on sequential dependencies but rather on networks of stored forms are learnable by children with DLD as well as by adults.

The Impact of Stimulus Length in Tongue and Lip Movement Pattern Stability in Amyotrophic Lateral Sclerosis.

PURPOSE: This study aimed to investigate the effect of stimulus signal length on tongue and lip motion pattern stability in speakers diagnosed with amyotrophic lateral sclerosis (ALS) compared to healthy controls. METHOD: Electromagnetic articulography was used to derive articulatory motion patterns from individuals with mild (n = 27) and severe (n = 16) ALS and healthy controls (n = 25). The spatiotemporal index (STI) was used as a measure of articulatory stability. Two experiments were conducted to evaluate signal length effects on the STI: (a) the effect of the number of syllables on STI values and (b) increasing lengths of subcomponents of a single phrase. Two-way mixed analyses of variance were conducted to assess the effects of syllable length and group on the STI for the tongue tip (TT), tongue back (TB), and lower lip (LL). RESULTS: Experiment 1 showed a significant main effect of syllable length (TT, p < .001; TB, p < .001; and LL, p < .001) and group (TT, p = .037; TB, p = .007; and LL, p = .017). TB and LL stability was generally higher with speech stimuli that included a greater number of syllables. Articulatory variability was significantly higher in speakers diagnosed with ALS compared to healthy controls. Experiment 2 showed a significant main effect of length (TT, p < .001; TB, p = .015; and LL, p < .001), providing additional support that STI values tend to be greater when calculated on longer speech signals. CONCLUSIONS: Articulatory stability is influenced by the length of speech signals and manifests similarly in both healthy speakers and persons with ALS. TT stability may be significantly impacted by phonemic content due to greater movement flexibility. Compared to healthy controls, there was an increase in articulatory variability in those with ALS, which likely reflects deviations in speech motor control. SUPPLEMENTAL MATERIAL: https://doi.org/10.23641/asha.24463924.

Neuromuscular adaptations of swallowing and speech in unilateral cerebral palsy: shared and distinctive traits.

Our aims were to 1) examine the neuromuscular control of swallowing and speech in children with unilateral cerebral palsy (UCP) compared with typically developing children (TDC), 2) determine shared and separate neuromuscular underpinnings of the two functions, and 3) explore the relationship between this control and behavioral outcomes in UCP. Surface electromyography (sEMG) was used to record muscle activity from the submental and superior and inferior orbicularis oris muscles during standardized swallowing and speech tasks. The variables examined were normalized mean amplitude, time to peak amplitude, and bilateral synchrony. Swallowing and speech were evaluated using standard clinical measures. Sixteen children with UCP and 16 TDC participated (7-12 yr). Children with UCP demonstrated higher normalized mean amplitude and longer time to peak amplitude across tasks than TDC (P < 0.01; and P < 0.02) and decreased bilateral synchrony than TDC for swallows (P < 0.01). Both shared and distinctive neuromuscular patterns were observed between swallowing and speech. In UCP, higher upper lip amplitude during swallows was associated with shorter normalized mealtime durations, whereas higher submental bilateral synchrony was related to longer mealtime durations. Children with UCP demonstrate neuromuscular adaptations for swallowing and speech, which should be further evaluated for potential treatment targets. Furthermore, both shared and distinctive neuromuscular underpinnings between the two functions are documented.NEW & NOTEWORTHY Systematically studying the swallowing and speech of children with UCP is new and noteworthy. We found that they demonstrate neuromuscular adaptations for swallowing and speech compared with typically developing peers. We examined swallowing and speech using carefully designed tasks, similar in motor complexity, which allowed us to directly compare patterns. We found shared and distinctive neuromuscular patterns between swallowing and speech.

Children With Developmental Language Disorder Show Deficits in the Production of Musical Rhythmic Groupings.

PURPOSE: Children with developmental language disorder (DLD) show evidence of domain-general deficits in sequentially patterned motor skills. This study focuses on the production of rhythmically grouped sequences drawn from a music task, with the hypothesis that children with DLD will show a sequential pattern learning deficit that crosses language and action domains. METHOD: Fifty-seven 4- to 5-year-old children (36 with DLD) drummed and clapped a developmentally appropriate musical rhythmic sequence 24 times (clapped 12 times, drummed 12 times). The accuracy of rhythmic events (markings of claps, drums, and pauses in a target sequence) was assessed through a modification of classic speech and language transcription procedures. The variability and prosodic structure of the rhythmic groupings were also measured. RESULTS: Children with DLD produced less accurate and more variable rhythmic groupings compared to their typically developing (TD) peers. While the final-position grouping of the sequence was especially vulnerable for all children, those with DLD included more co-occurring errors in initial and final groupings of the same rhythmic sequence. Both TD children and children with DLD were less accurate in the clapping than the drumming task. Neither rhythmic drumming nor clapping accuracy correlated with motor skill in either group of children. CONCLUSIONS: This study provides novel evidence of a manual rhythmic grouping deficit in DLD, one that is motivated by language-not motor or speech-factors. Cognitive abilities necessary to organize rhythmic events into higher order groupings are impaired across music and language in children with DLD. Rhythmic organization and sequencing may serve an important role in diagnosis and intervention in this population. SUPPLEMENTAL MATERIAL: https://doi.org/10.23641/asha.24158745.

Shared and Separate Neuromuscular Underpinnings of Swallowing and Motor Speech Development in the School-Age Years.

PURPOSE: Despite co-occurrence of swallowing and speech disorders in childhood, there is limited research on shared and separate neuromuscular underpinnings of these functions. The purpose of this study was to (a) compare neuromuscular control of swallowing and speech between younger and older children and (b) determine similarities and differences in neuromuscular control of swallowing and speech. METHOD: Twenty-six typically developing children (thirteen 7- to 8-year-olds and thirteen 11- to 12-year-olds) completed this cross-sectional study. Neuromuscular control was evaluated using surface electromyography of submental muscles and superior and inferior orbicularis oris muscles during parallel tasks of swallowing and speech. Outcome measures included normalized mean amplitude, burst duration, time to peak amplitude, and bilateral synchrony, which were examined using mixed-effects models. RESULTS: For normalized mean amplitude, burst duration, and time to peak amplitude, there were significant two- and three-way interactions between muscle group, task, and age group, indicating that older and younger children demonstrated different muscle activation patterns, and these patterns varied by muscle and task. No differences were noted between groups for bilateral synchrony. For parallel tasks, children demonstrated different magnitudes of normalized mean amplitude and time to peak amplitude of speech and swallowing. However, they demonstrated a similar pattern: increases in magnitude as task complexity increased. CONCLUSIONS: Children continue to demonstrate refinement of their neuromuscular control of swallowing and speech between 7-8 and 11-12 years of age, and there are both shared and separate elements of neuromuscular control between these two vital functions. To improve generalizability of findings, future research should include longitudinal analysis of swallowing and speech development, as well as measures of central neurophysiology. SUPPLEMENTAL MATERIAL: https://doi.org/10.23641/asha.23796258.

Phonological and Articulatory Deficits in the Production of Novel Signs in Children With Developmental Language Disorder.

PURPOSE: Sign language, like spoken language, incorporates phonological and articulatory (or motor) processing components. Thus, the learning of novel signs, like novel spoken word forms, may be problematic for children with developmental language disorder (DLD). In the present work, we hypothesize that phonological and articulatory deficits in novel sign repetition and learning would differentiate preschool-age children with DLD from their typical peers. METHOD: Children with DLD (n = 34; aged 4-5 years) and their age-matched typical peers (n = 21) participated. Children were exposed to four novel signs, all iconic, but only two linked to a visual referent. Children imitatively produced these novel signs multiple times. We obtained measures of phonological accuracy and articulatory motion stability as well as of learning of the associated visual referent. RESULTS: Children with DLD showed an increased number of phonological feature (i.e., handshape, path, and orientation of the hands) errors when compared with their typical peers. While articulatory variability did not overall differentiate children with DLD from typical peers, children with DLD showed instability in one novel sign that obligated bimanual oppositional movement. Semantic aspects of novel sign learning were unaffected in children with DLD. CONCLUSIONS: Deficits that have been documented in phonological organization of spoken words in children with DLD are also evident in the manual domain. Analyses of hand motion variability suggest that children with DLD do not show a generalized motor deficit, but one that is restricted to the implementation of coordinated and sequential hand motion.

Acoustic and Kinematic Methods of Indexing Spatiotemporal Stability in Children With Developmental Language Disorder.

PURPOSE: The spatiotemporal index (STI) is a standard metric for quantifying the stability and patterning of speech movements. The STI has often been applied to individual speech articulators, but an STI derived from the acoustic signal offers a composite and easily obtained measure that incorporates multiple components of the speech production complex. In this work, we examine the relationship between kinematic and acoustic STIs in children with and without developmental language disorder (DLD), with the aim of determining whether the acoustic and kinematic STIs reflect similar degrees of production variability. METHOD: A total of 85 children with DLD and with typical language development (or typically developing [TD] children), aged 4-8 years, were studied. In this methodological article, two experiments were conducted: one deliberately selected because group differences were observed in the kinematic STI (i.e., sentence production) and one in which there were no group differences in the kinematic STI (i.e., nonword production). These two experiments are representative of speech stability studies. The aim was to determine whether the acoustic STI (i.e., amplitude envelope) results aligned with those obtained via the kinematic STI (i.e., lip motion). RESULTS: In sentence production, most group differences aligned across kinematic and acoustic STI measures. The acoustic, but not the kinematic, STI showed higher variability in children with DLD compared with the 6-year-old TD group. In nonword production, neither the kinematic STI nor the acoustic STI differentiated children with DLD from TD children. In each experiment, the kinematic and acoustic STIs showed a moderate-to-strong correlation. CONCLUSIONS: The kinematic and acoustic STIs assess different components of speech movement patterning. However, the relationship between acoustic and kinematic spatiotemporal stability is strong in two tasks of varying linguistic complexity in children with and without DLD. These findings are promising for future experimental work in this area.

The Effect of Somatosensory Input on Word Recognition in Typical Children and Those With Speech Sound Disorder.

PURPOSE: Recent work suggests that speech perception is influenced by the somatosensory system and that oral sensorimotor disruption has specific effects on the perception of speech both in infants who have not yet begun to talk and in older children and adults with ample speech production experience; however, we do not know how such disruptions affect children with speech sound disorder (SSD). Response to disruption of would-be articulators during speech perception could reveal how sensorimotor linkages work for both typical and atypical speech and language development. Such linkages are crucial to advancing our knowledge on how both typically developing and atypically developing children produce and perceive speech. METHOD: Using a looking-while-listening task, we explored the impact of a sensorimotor restrictor on the recognition of words whose onsets involve late-developing sounds (s, ʃ) for both children with typical development (TD) and their peers with SSD. RESULTS: Children with SSD showed a decrement in performance when they held a restrictor in their mouths during the task, but this was not the case for children with TD. This effect on performance was only observed for the specific speech sounds blocked by the would-be articulators. CONCLUSION: We argue that these findings provide evidence for altered perceptual motor pathways in children with SSD. SUPPLEMENTAL MATERIAL: https://doi.org/10.23641/asha.21809442.

Swallowing and Motor Speech Skills in Unilateral Cerebral Palsy: Novel Findings From a Preliminary Cross-Sectional Study.

PURPOSE: Our purpose was to start examining clinical swallowing and motor speech skills of school-age children with unilateral cerebral palsy (UCP) compared to typically developing children (TDC), how these skills relate to each other, and whether they are predicted by clinical/demographic data (age, birth history, lesion type, etc.). METHOD: Seventeen children with UCP and 17 TDC (7-12 years old) participated in this cross-sectional study. Feeding/swallowing skills were evaluated using the Dysphagia Disorder Survey (DDS) and a normalized measure of mealtime efficiency (normalized mealtime duration, i.e., nMD). Motor speech was assessed via speech intelligibility and speech rate measures using the Test of Children's Speech Plus. Analyses included nonparametric bootstrapping, correlation analysis, and multiple regression. RESULTS: Children with UCP exhibited more severe (higher) DDS scores (p = .0096, Part 1; p = .0132, Part 2) and reduced speech rate than TDC (p = .0120). Furthermore, in children with UCP, total DDS scores were moderately negatively correlated with speech intelligibility (words: r = -.6162, p = .0086; sentences: r = -.60792, p = .0096). Expressive language scores were the only significant predictor of feeding and swallowing performance, and receptive language scores were the only significant predictor of motor speech skills. CONCLUSIONS: Swallowing and motor speech skills can be affected in school-age children with UCP, with wide variability of performance also noted. Preliminary cross-system interactions between swallowing, speech, and language are observed and might support the complex relationships between these domains. Further understanding these relationships in this population could have prognostic and/or therapeutic value and warrants further study.

Phonological characteristics of novel gesture production in children with developmental language disorder: Longitudinal findings.

Children with developmental language disorder (DLD; aka specific language impairment) are characterized based on deficits in language, especially morphosyntax, in the absence of other explanatory conditions. However, deficits in speech production, as well as fine and gross motor skill, have also been observed, implicating both the linguistic and motor systems. Situated at the intersection of these domains, and providing insight into both, is manual gesture. In the current work, we asked whether children with DLD showed phonological deficits in the production of novel gestures and whether gesture production at 4 years of age is related to language and motor outcomes two years later. Twenty-eight children (14 with DLD) participated in a two-year longitudinal novel gesture production study. At the first and final time points, language and fine motor skills were measured and gestures were analyzed for phonological feature accuracy, including handshape, path, and orientation. Results indicated that, while early deficits in phonological accuracy did not persist for children with DLD, all children struggled with orientation while handshape was the most accurate. Early handshape and orientation accuracy were also predictive of later language skill, but only for the children with DLD. Theoretical and clinical implications of these findings are discussed.

Influences of Methodological Decisions on Assessing the Spatiotemporal Stability of Speech Movement Sequences.

PURPOSE: The spatiotemporal index (STI) is a widely used approach for measuring speech pattern stability across multiple repetitions of a stimulus. In this study, we examine how methodological choices in the implementation of the STI (including the number of repetitions, length of stimuli, and parsing procedure) can affect its value. METHOD: To evaluate how each methodological decision affects the STI, we use a synthetic data framework that allows for the generation of random productions of the template phrase "Buy Bobby a Puppy" at different stability levels. Within this framework, we conduct three experiments: Experiment 1 investigates the effects of the number of repetitions, Experiment 2 investigates the effects of stimulus length, and Experiment 3 investigates the effects of parsing errors. RESULTS: In Experiment 1, we observed that STI values based on fewer repetitions will systematically underestimate larger repetition estimates. Experiment 2 showed that STI values will tend to be higher when calculated on longer (multimovement) stimuli independent of any differences in the stability of the underlying speech patterns. Finally, in Experiment 3, we showed that even minor parsing errors (≈ 10 ms) increase the value of the STI. CONCLUSIONS: The results of this study illustrate that even minor choices in the implementation of the STI can have a noticeable impact on the resulting value. These findings highlight the care that needs to be taken when designing studies and comparing STI values across studies to ensure that different STI values are capturing real differences in motion pattern stability rather than trivial methodological variation.

Contributions of early motor deficits in predicting language outcomes among preschoolers with developmental language disorder.

Purpose: We assessed the extent to which language, speech, and fine/gross motor skills in preschoolers with developmental language disorder (DLD; also referred to as specific language impairment) predicted language outcome two years later.Method: Participants with DLD (n = 15) and typical development (TD; n = 14) completed language, speech, and fine/gross motor assessments annually, beginning as 4- to 5-year-olds (Year 1 timepoint) and continuing through 6 to 7 years of age (Year 3 timepoint). We performed Pearson correlation and hierarchical regression analyses to examine the relative contributions of Year 1 language, speech, and motor skills to Year 3 language outcome in each group.Result: Among children with DLD, Year 1 fine/gross motor scores positively correlated with Year 3 language scores, uniquely explaining 40% of the variance in language outcomes. Neither Year 1 language, speech-sound, nor speech-motor scores predicted language outcome in this group. Among children with TD, only Year 1 language predicted language outcome.Conclusion: This small longitudinal study reveals that, among preschoolers with DLD, certain early fine/gross motor deficits predict persistent language impairment. Future research that includes larger sample sizes and motor tasks that incorporate complex sequencing will enhance the understanding of the relationship between language, speech, and motor skills; specifically, whether certain motor deficits simply co-occur with language deficits or whether they are tied to DLD through shared impairments in sequential learning mechanisms.

A longitudinal study of the phonological organisation of novel word forms in children with developmental language disorder.

Purpose: Deficits in the production of novel words, such as in nonword repetition tasks, are one of the early hallmarks of developmental language disorder (DLD). In children with DLD, the production of novel nonwords is characterised by speech sound inaccuracy. The focus of the present study is on the stable organisation of phonological sequences. Specifically, we aimed to identify the persistence of deficits in accuracy and in variability in sound sequencing in novel word production from pre-school to the early school years.Method: Children with and without DLD produced a set of six nonwords 12 times each, initially collected when children were 4- to 5-years old. Children repeated this task over the course of two years. Analyses included phonetic accuracy as well as network science indices of sound sequence organisation.Result: Children with DLD were less accurate than their peers with typical language at each timepoint, and their productions were markedly variable, as revealed by network science metrics; these children never converged with their peers with typical language.Conclusion: The findings suggest a unique deficit in phonological sequence production that persists beyond the pre-school years. These results offer new theoretical and clinical insights into mechanisms that underlie deficits in novel word form learning.

Not All Procedural Learning Tasks Are Difficult for Adults With Developmental Language Disorder.

Purpose The experiment reported here compared two hypotheses for the poor statistical and artificial grammar learning often seen in children and adults with developmental language disorder (DLD; also known as specific language impairment). The procedural learning deficit hypothesis states that implicit learning of rule-based input is impaired, whereas the sequential pattern learning deficit hypothesis states that poor performance is only seen when learners must implicitly compute sequential dependencies. The current experiment tested learning of an artificial grammar that could be learned via feature activation, as observed in an associatively organized lexicon, without computing sequential dependencies and should therefore be learnable on the sequential pattern learning deficit hypothesis, but not on the procedural learning deficit hypothesis. Method Adults with DLD and adults with typical language development (TD) listened to consonant-vowel-consonant-vowel familiarization words from one of two artificial phonological grammars: Family Resemblance (two out of three features) and a control (exclusive OR, in which both consonants are voiced OR both consonants are voiceless) grammar in which no learning was predicted for either group. At test, all participants rated 32 test words as to whether or not they conformed to the pattern in the familiarization words. Results Adults with DLD and adults with TD showed equal and robust learning of the Family Resemblance grammar, accepting significantly more conforming than nonconforming test items. Both groups who were familiarized with the Family Resemblance grammar also outperformed those who were familiarized with the OR grammar, which, as predicted, was learned by neither group. Conclusion Although adults and children with DLD often underperform, compared to their peers with TD, on statistical and artificial grammar learning tasks, poor performance appears to be tied to the implicit computation of sequential dependencies, as predicted by the sequential pattern learning deficit hypothesis.

Vowel Accuracy and Segmental Variability Differentiate Children With Developmental Language Disorder in Nonword Repetition.

Purpose Poor nonword repetition accuracy is a hallmark of children with developmental language disorder (DLD). However, other diagnostic categories also show impaired nonword repetition performance relative to children with typical development (TD); therefore, this task is currently a sensitive but nonspecific index of DLD. In this study, we investigated segmental and kinematic aspects of nonword repetition performance to further specify the diagnostic utility of nonword repetition tasks (NRTs) in diagnosing DLD. Method Forty children, ages 48-86 months, participated, including children with DLD (n = 12), speech sound disorder (SSD; n = 14), and TD (n = 14). All children completed an assessment battery to determine group classification, a classic NRT (Dollaghan & Campbell, 1998), and an experimental NRT designed to measure segmental and articulatory (specifically lip aperture) variability. We assessed nonword repetition accuracy in the classic and experimental NRTs and segmental and kinematic variability in the experimental NRT. Results In both the classic and experimental NRTs, children with SSD and DLD produced nonwords with lower phoneme and consonant accuracy compared to children with TD. Children with DLD produced more vowel errors compared to children with TD in both tasks. In the experimental NRT, children with DLD produced nonwords with high levels of segmental variability compared to children with TD. Children with SSD did not differ from children with TD or children with DLD in the vowel accuracy or the segmental variability measures. The articulatory variability measure did not reveal any group differences. Conclusions In the presence of speech sound difficulties, low nonword repetition accuracy does not aid in the diagnosis of DLD. However, vowel accuracy and segmental variability appear specific to DLD status in NRTs.

Lexical-Semantic Cues Induce Sound Pattern Stability in Children With Developmental Language Disorder.

Purpose When learning novel word forms, preschoolers with developmental language disorder (DLD; also known as specific language impairment) produce speech targets inaccurately and with a high degree of intraword variability. The aim of the current study is to specify whether and how layering lexical-semantic information onto novel phonological strings would induce increased organization of sound production patterns. Method Twenty-one preschoolers with DLD and 21 peers with typical language (ranging in age from 4;1 to 5;11 [years;months]) imitated multiple renditions of novel words, half with (i.e., words) and half without (i.e., nonwords) a linked visual referent. Methods from network science were used to assess the stability and patterning of syllable sequences. Sound accuracy was also measured. Results Children with DLD were less accurate and more variable than their typical peers. However, once word forms were associated with a visual referent, network stability, but not accuracy, improved for children with DLD. Conclusions Children with DLD showed significant word form deficits as they acquired novel words and nonwords. The inclusion of a meaningful referent resulted in increased sound sequence stability, suggesting that lexical-semantic information provides a bootstrap for phonological organization in children with DLD.

Language Skill Mediates the Relationship Between Language Load and Articulatory Variability in Children With Language and Speech Sound Disorders.

Purpose: The aim of the study was to investigate the relationship between language load and articulatory variability in children with language and speech sound disorders, including childhood apraxia of speech. Method: Forty-six children, ages 48-92 months, participated in the current study, including children with speech sound disorder, developmental language disorder (aka specific language impairment), childhood apraxia of speech, and typical development. Children imitated (low language load task) then retrieved (high language load task) agent + action phrases. Articulatory variability was quantified using speech kinematics. We assessed language status and speech status (typical vs. impaired) in relation to articulatory variability. Results: All children showed increased articulatory variability in the retrieval task compared with the imitation task. However, only children with language impairment showed a disproportionate increase in articulatory variability in the retrieval task relative to peers with typical language skills. Conclusion: Higher-level language processes affect lower-level speech motor control processes, and this relationship appears to be more strongly mediated by language than speech skill.

An Application of Network Science to Phonological Sequence Learning in Children With Developmental Language Disorder.

Purpose: Network science has been a valuable tool in language research for investigating relationships between complex linguistic elements but has not yet been applied to sound sequencing in production. In the present work, we used standard error-based accuracy and articulatory kinematic approaches as well as novel measures from network science to evaluate variability and sequencing errors in speech production in children with developmental language disorder (DLD; aka specific language impairment). Method: Twelve preschoolers with DLD and 12 age-matched controls participated in a 3-day novel word learning study. Transcription and articulatory movement data were collected to measure accuracy and variability of productions, and networks of speech productions were generated to analyze syllable co-occurrence patterns. Results: Results indicated that children with DLD were less accurate than children with typical language at the segmental level. Crucially, these findings did not align with performance at the articulatory level, where there were no differences in movement variability between children with DLD and those with typical language. Network analyses revealed characteristics that were not captured by standard measures of phonetic accuracy, including a larger inventory of syllable forms, more connections between the forms, and less consistent production patterns. Conclusions: Network science provides significant insights into phonological learning trajectories in children with DLD and their typically developing peers. Importantly, errors in word production by children with DLD do not surface as a result of weakness in articulatory control. Instead, results suggest that speech errors in DLD may relate to deficits in sound sequencing.

The impact of brief restriction to articulation on children's subsequent speech production.

This project explored whether disruption of articulation during listening impacts subsequent speech production in 4-yr-olds with and without speech sound disorder (SSD). During novel word learning, typically-developing children showed effects of articulatory disruption as revealed by larger differences between two acoustic cues to a sound contrast, but children with SSD were unaffected by articulatory disruption. Findings suggest that, when typically developing 4-yr-olds experience an articulatory disruption during a listening task, the children's subsequent production is affected. Children with SSD show less influence of articulatory experience during perception, which could be the result of impaired or attenuated ties between perception and articulation.