The sensitivity of children with SLI to phonotactic probabilities during lexical access

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.

Identifying Linguistic Markers of French-Speaking Teenagers With Developmental Language Disorder: Which Tasks Matter?

PURPOSE

This research aimed to identify reliable tasks discriminating French-speaking adolescents with developmental language disorder (DLD) from their peers with typical language (TL) and to assess which linguistic domains represent areas of particular weakness in DLD. Unlike English, morphosyntax has not been identified as a special area of weakness when compared with lexicosemantics in French preschoolers with DLD. Since there is evidence that subject-verb number agreement is consolidated in later childhood, one might expect morphosyntax to be a particular weakness and marker of French DLD only in (pre)adolescence.

METHOD

We administered 20 subtasks that assessed linguistic and phonological working memory skills of two groups: 17 adolescents clinically identified as having DLD (M = 14.1 years) and 20 (pre)teens with TL (M = 12.2 years). Using robust statistics that are less affected by outliers, we selected the most discriminating subtasks between our groups, calculated their optimal cutoff score, and derived diagnostic accuracy statistics. We combined these subtasks in a multivariable model to identify which subtasks contributed the most to the identification of DLD.

RESULTS

Seven subtasks were selected as discriminating between our groups, and three showed outstanding diagnostic accuracy: Recalling Sentences, a multiword task assessing lexicosemantic skills, and a subject-verb number agreement production task. When combined, we found that the latter contributed the most to our multivariable model.

CONCLUSION

This study provides evidence that the most relevant markers to identify DLD in French teenagers are tasks assessing lexicosemantics and morphosyntactic domains, and that morphosyntax should be considered an important area of weakness in French-speaking teenagers with DLD.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.21753932.

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.

Explicit Instructions Do Not Enhance Auditory Statistical Learning in Children With Developmental Language Disorder: Evidence From Event-Related Potentials

A current issue in psycholinguistic research is whether the language difficulties exhibited by children with developmental language disorder [DLD, previously labeled specific language impairment (SLI)] are due to deficits in their abilities to pick up patterns in the sensory environment, an ability known as statistical learning (SL), and the extent to which explicit learning mechanisms can be used to compensate for those deficits. Studies designed to test the compensatory role of explicit learning mechanisms in children with DLD are, however, scarce, and the few conducted so far have led to inconsistent results. This work aimed to provide new insights into the role that explicit learning mechanisms might play on implicit learning deficits in children with DLD by resorting to a new approach. This approach involved not only the collection of event-related potentials (ERPs), while preschool children with DLD [relative to typical language developmental (TLD) controls] were exposed to a continuous auditory stream made of the repetition of three-syllable nonsense words but, importantly, the collection of ERPs when the same children performed analogous versions of the same auditory SL task first under incidental (implicit) and afterward under intentional (explicit) conditions. In each of these tasks, the level of predictability of the three-syllable nonsense words embedded in the speech streams was also manipulated (high vs. low) to mimic natural languages closely. At the end of both tasks' exposure phase, children performed a two-alternative forced-choice (2-AFC) task from which behavioral evidence of SL was obtained. Results from the 2-AFC tasks failed to show reliable signs of SL in both groups of children. The ERPs data showed, however, significant modulations in the N100 and N400 components, taken as neural signatures of word segmentation in the brain, even though a detailed analysis of the neural responses revealed that only children from the TLD group seem to have taken advantage of the previous knowledge to enhance SL functioning. These results suggest that children with DLD showed deficits both in implicit and explicit learning mechanisms, casting doubts on the efficiency of the interventions relying on explicit instructions to help children with DLD to overcome their language difficulties.

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.

Auditory Lexical Decisions in Developmental Language Disorder: A Meta-Analysis of Behavioral Studies

PURPOSE

Despite the apparent primacy of syntactic deficits, children with developmental language disorder (DLD) often also evidence lexical impairments. In particular, it has been argued that this population have difficulty forming lexical representations that are detailed enough to support effective spoken word processing. In order to better understand this deficit, a meta-analysis of studies testing children with DLD in the auditory lexical decision task was conducted. The objective was to provide summary effect size estimates for accuracy and response time measures for comparisons to age- and language-matched control groups.

METHOD

Two thousand three hundred seventy-two records were initially identified through electronic searches and expert consultation, with this cohort reduced to 9 through duplicate removal and the application of eligibility and quality criteria. The final study cohort included 499 children aged 3;8-11;4 (years;months).

RESULTS

Multivariate analysis suggests that children with DLD were significantly less accurate in the auditory lexical decision task than age-matched controls. For the response time estimate, however, confidence intervals for the same group comparison crossed 0, suggesting no reliable difference between groups. Confidence intervals also crossed 0 for language-matched control estimates for both accuracy and response time, suggesting no reliable difference between groups on either measure.

CONCLUSION

Results broadly support the hypothesis that children with DLD have difficulty in forming detailed lexical representations relative to age- though not language-matched peers. However, further work is required to determine the performance profiles of potential subgroups and the impact of manipulating different lexical characteristics, such as the position and degree of nonword error, phonotactic probability, and semantic network size.

Neighborhood Density and Syntactic Class Effects on Spoken Word Recognition: Specific Language Impairment and Typical Development

PURPOSE

The purpose of the current study was to determine the effect of neighborhood density and syntactic class on word recognition in children with specific language impairment (SLI) and typical development (TD).

METHOD

Fifteen children with SLI (M age = 6;5 [years;months]) and 15 with TD (M age = 6;4) completed a forward gating task that presented consonant-vowel-consonant dense and sparse (neighborhood density) nouns and verbs (syntactic class).

RESULTS

On all dependent variables, the SLI group performed like the TD group. Recognition performance was highest for dense words and nouns. The majority of 1st nontarget responses shared the 1st phoneme with the target (i.e., was in the target's cohort). When considering the ranking of word types from easiest to most difficult, children showed equivalent recognition performance for dense verbs and sparse nouns, which were both easier to recognize than sparse verbs but more difficult than dense nouns.

CONCLUSION

The current study yields new insight into how children access lexical-phonological information and syntactic class during the process of spoken word recognition. Given the identical pattern of results for the SLI and TD groups, we hypothesize that accessing lexical-phonological information may be a strength for children with SLI. We also discuss implications for using the forward gating paradigm as a measure of word recognition.