Quantifying the relative contributions of lexical and phonological factors to regular past tense accuracy

Neural Correlates of Telicity in Spanish-Speaking Children with and without Developmental Language Disorder

BACKGROUND

It is broadly acknowledged that children with Developmental Language Disorder (DLD) show verb-related limitations. While most previous studies have focused on tense, the mastery of lexical aspect-particularly telicity-has not been the primary focus of much research. Lexical aspect refers to whether an action has a defined endpoint (telic verbs) or not (atelic verbs).

OBJECTIVE

This study investigates the effect of telicity on verb recognition in Chilean children with DLD compared to their typically developing (TD) peers using the Event-Related Potential (ERP) technique.

METHOD

The research design is a mixed factorial design with between-group factors of 2 (DLD/TD) and within-group factors of 2 (telic/atelic verbs) and 2 (coherent/incoherent sentences). The participants were 36 school-aged children (18 DLD, 18 TD) aged 7 to 7 years and 11 months. The task required subjects to listen to sentences that either matched or did not match an action in a video, with sentences including telic or atelic verbs.

RESULTS

The study found notable differences between groups in how they processed verbs (N400 and post-N400 components) and direct objects (N400 and P600 components).

CONCLUSIONS

Children with DLD struggled to differentiate telic and atelic verbs, potentially because they employed overgeneralization strategies consistent with the Event Structural Bootstrapping model.

Verbs Matter: A Tutorial for Determining Verb Difficulty

PURPOSE

Research indicates that when teaching grammatical forms to children, the verbs used to model specific grammatical inflections matter. When learning grammatical forms, children have higher performance when they hear many unique verb forms that vary in their frequency and phonological complexity. In this tutorial, we demonstrate a method for identifying and characterizing a large number of verbs based on their frequency and complexity.

METHOD

We selected verbs from an open-access database of transcribed child language samples. We extracted verbs produced by 5- to 8.9-year-old children in four morphosyntactic contexts: regular past tense -ed, third person singular -s, is/are + verb+ing, and do/does questions. We ranked verbs based on their frequency of occurrence across transcripts. We also coded the phonological complexity of each verb. We coded each verb as high or low frequency and high or low phonological complexity.

RESULTS

The synthesis yielded 129 unique verbs used in the regular past tense -ed context, 107 verbs used in the third person singular -s context, 69 verbs used in the is/are + verb+ing context, and 16 verbs used in the do/does question context. We created tables for each form that include the frequency rankings and phonological complexity scores for every verb.

CONCLUSIONS

Clinicians may use the verb lists, frequency ratings, and phonological complexity scores to help identify verbs to incorporate into assessment and intervention sessions with children. Researchers and clinicians may use the step-by-step approach presented in the tutorial to identify verbs or other syntactic components used in different morphosyntactic contexts or produced by individuals of different demographics in different speaking contexts.

Pattern-Based Target Selection for Treatment of Irregular Past Tense: A Single-Case Experimental Design for Children With Developmental Language Disorder

PURPOSE

Many children with developmental language disorder (DLD) demonstrate difficulty inflecting irregular past tense verbs. We evaluated using phonological-based patterns (i.e., schemas) to select targets for treatment of irregular verb inflection for children with DLD. We hypothesized this approach would result in acquisition of treated verbs, generalization to untreated verbs within the same phonological schema, and increased use of correct irregular verbs in naturalistic contexts.

METHOD

Treatment was provided to three 7-year-old participants with DLD in the context of multiple baseline designs across behaviors and participants. Phonological schemas included vowel change, final alveolar, and dual change irregular verbs. Treatment was provided using established therapeutic approaches, including narrative generation, sentence imitation, and naturalistic play activities. Acquisition of treated and untreated targets was assessed at the beginning of sessions, and use of verbs in naturalistic contexts was observed throughout treatment sessions.

RESULTS

Positive acquisition effects were noted for two of three participants. Generalization to untreated items occurred within and across treatment sets for two participants, whereas increases in accurate irregular verb production in naturalistic contexts were not observed.

CONCLUSIONS

Outcomes demonstrated support for a pattern-based approach to target selection for treatment of irregular past tense verbs. One participant, who demonstrated general difficulty with the probe and treatment tasks, showed no treatment effect, suggesting that the treatment may be effective for some children with DLD. Further research is warranted to determine what factors might have influenced these variable outcomes across participants.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.23671500.

When Children's Production Deviates From Observed Input: Modeling the Variable Production of the English Past Tense

As children gradually master grammatical rules, they often go through a period of producing form-meaning associations that were not observed in the input. For example, 2- to 3-year-old English-learning children use the bare form of verbs in settings that require obligatory past tense meaning while already starting to produce the grammatical -ed inflection. While many studies have focused on overgeneralization errors, fewer studies have attempted to explain the root of this earlier stage of rule acquisition. In this work, we use computational modeling to replicate children's production behavior prior to the generalization of past tense production in English. We illustrate how seemingly erroneous productions emerge in a model, without being licensed in the grammar and despite the model aiming at conforming to grammatical forms. Our results show that bare form productions stem from a tension between two factors: (1) trying to produce a less frequent meaning (the past tense) and (2) being unable to restrict the production of frequent forms (the bare form) as learning progresses. Like children, our model goes through a stage of bare form production and then converges on adult-like production of the regular past tense, showing that these different stages can be accounted for through a single learning mechanism.

Word-final complexity in speech sound intervention: two case studies

In speech sound intervention, consonant clusters promote generalisation (i.e. improvement in untreated sounds and words), ostensibly due to their relative complexity compared to other phonological targets. However, our understanding of clusters as intervention targets is largely restricted to those in word-initial position (e.g. [fl-], flip). The present study extends available work to consider the effects of word-final consonant cluster targets (e.g. [-ks]). Phonologically complex word-final clusters may be morphologically simple (e.g. mix) or morphologically complex (e.g. packs, inflected with third-person singular) - yet this cross-domain complexity remains an understudied phenomenon. Presently, two case studies provide an initial investigation of word-final cluster intervention targets for children with phonologically based speech sound disorders. Intervention targets for both Anna (3;7 [years;months]) and David (4;1) featured the phonologically complex word-final cluster [-ks], with Anna's target being morphologically simple and David's being morphologically complex. Intervention was provided in 45-minute, individual sessions three times per week for a maximum of 18 sessions. Both children demonstrated high target accuracy by intervention's end. Following intervention, both children demonstrated progress in intelligibility and ability to produce word-final consonant clusters; David further demonstrated generalisation across multiple measures. Results are interpreted with consideration of individual differences and existing research on complexity in phonological intervention. Overall, present findings motivate continued research, as manipulation of word-final complexity allows for emphasis on a context that is relevant for children with speech sound disorders, for peers with difficulties in morphology (including word-final grammatical morphemes) and for the substantial proportion of children demonstrating weaknesses in both domains.

A profile of expressive inflectional morphology in early school-age children with developmental language disorder

Previous research has established that children with developmental language disorder (DLD) have difficulties producing inflectional morphology, in particular, finiteness marking. However, other categories of inflectional morphology, such as possessive 's nominal inflection remain relatively unexplored. Analyses of the characteristics for marking inflection, such as allomorphic categories, may increase our understanding of patterns within disordered grammar to inform the design of interventions and target selection. Data from n = 30 early school-aged children (M = 75 months, SD = 3.38, range = 69-81 months) with DLD were analysed to develop a profile of inflectional morphology skills. Morphological categories included expressive regular past tense, third person singular, and possessive 's. Skills were profiled using an elicitation task. The relationships between expressive morphosyntax, and phonological short-term memory and working memory were also explored. Children demonstrated low accuracy in performance across all inflectional categories, including possessive 's. There were no significant differences between productions of different morphemes, but syllabic allomorphs ([əd]; [əz]) were produced with significantly lower accuracy than segmental allomorphs ([d], [t]; [z], [s]) across all morphological categories. All correlations between expressive morphosyntax and measures of memory were non-significant. Children with DLD show broad deficits in the ability to mark for inflection, including possessive 's; this has implications for theories explaining DLD. Findings may contribute to the design of urgently needed interventions for this clinical population.

Evaluating two different dose frequencies and cumulative intervention intensities to improve past tense production for early school-aged children with developmental language disorder

AIMS

This study compared two dose frequency conditions of an explicit intervention with 50 trials per session designed to improve past tense marking in early school-aged children with developmental language disorder (DLD). The influence of allomorphs on intervention effects was also examined.

METHODS

Data from previously conducted intervention studies were combined and analysed. Participants included nine children (mean age = 6;5 years) who received 20-30-min intervention sessions provided twice per week for 10 weeks (1000 trials; 400-600 min) and 20 children (mean age = 6;6) who received 20-30-min intervention sessions provided once per week for 10 weeks (500 trials; 200-300 min). Repeated measures included criterion-referenced probes for production of untrained past tense verbs collected throughout baseline, intervention, and maintenance phases. The rate of progress in each phase was analysed using logistic regression. The proportion of participants who produced past tense allomorphs correctly at pre-intervention, post-intervention, and maintenance testing points was analysed.

RESULTS

Logistic regression showed a stable baseline, highly significant progress during the intervention phase, and a marginally significant shallow decline during the maintenance phase. Those in the twice per week group showed a greater rate of progress during the intervention phase leading to significantly higher scores in the maintenance period when compared with the once per week group. The allomorphic category of past tense verbs did not appear to influence outcomes.

CONCLUSIONS

Participants receiving intervention twice per week appeared to demonstrate a greater rate of progress with intervention than those receiving it once per week, although once per week was also effective. However, these results should be interpreted with caution. Limitations to study design indicate that a larger randomised controlled trial is required. All past tense allomorphs improve to a similar degree when treated with this intervention.

WHAT THIS PAPER ADDS

What is already known on the subject Understanding the parameters of dosage and intensity are important for clinical practice. Research evaluating the efficacy and/or effectiveness of interventions delivered in different dose/intensity conditions is scarce. There appears to be different interpretations of what constitutes dosage and intensity in published research. What this paper adds to existing knowledge This study retrospectively compared dosage and intensity conditions of intervention provided twice per week to intervention provided once per week. Both dose frequencies could be delivered in clinical settings. Results from this study were analysed by grouping data from multiple testing points, rather than comparing pre-post results. This approach demonstrated the variability of individual performance that would otherwise be lost with conventional methods of analysis. This study demonstrated that all past tense allomorphs improve to a similar degree when treated with this intervention. What are the potential or actual clinical implications of this work? Parameters of dosage and intensity are still not clearly defined well enough for translation to clinical practice. In consideration of current research, this intervention may be more effective if delivered twice per week. If clinicians are treating past tense, all allomorphs should be considered as priorities for intervention targets.

Diagnosis of Developmental Language Disorder in Research Studies

Purpose The aim of this study was to investigate the extent to which researchers in the field of developmental language disorder are utilizing validated methods to diagnose their research participants. Method We examined 90 research articles published from 2015 to 2019 that included English-speaking participants from the United States who were identified as having a developmental language disorder or specific language impairment. From these articles, we identified the tests and measures used to identify participants and classify them as healthy or impaired. We then consulted the test manuals and the literature to find information on sensitivity and specificity of the test and the evidence-based cut score that maximized identification accuracy. Results Of the 90 articles examined, 38 (42%) were found to reflect validated diagnostic methods, and 51 (58%) did not. Conclusion Our results illustrate that validated methods are used less than half of the time even by those who should have a high level of expertise and despite calls for increasing scientific rigor in research practices.

Insights Into Category Sorting Flexibility in Bilingual Children: Results of a Cognitive Lab Study

Purpose The purpose of this study was to explore how bilingual children shift sets to gain flexibility when forming categories. Using a cognitive lab approach focused on understanding how learners approach problems, we asked children to sort 10 sets of pictures representing common objects in two different ways and to explain their rationale for the sort. We explored the relationship between age and language use on their performance. Method Forty-six typically developing Spanish-English bilingual children (25 girls, 21 boys) participated in the study. They ranged in age from 4;0 to 10;11 (years;months). Receptive and expressive responses to a novel category sorting task were collected. Results Forty-four of the 46 children tested were able to perform the category sorting task. Within language, receptive and expressive category sorting scores were positively and significantly correlated while only expressive scores were significantly associated across languages. There were significant correlations between the sorting scores and age and language output and input. Children's ability to provide expressive responses explaining their sort strategy was moderately correlated with their language experience, especially English output. Conclusions The category sorting task proved useful in eliciting sorting behaviors and naming from the children tested. The age effect suggests that sorting may reflect their general developmental experience rather than their language-specific experience. The cognitive lab approach allowed us to understand how children shift sets and verbalize their understanding of the categorization process. Knowing how children approach this task can inform future work to develop ways to strategically select language intervention goals and document progress.

Five overarching factors central to grammatical learning and treatment in children with developmental language disorder

BACKGROUND

During grammatical treatment of children with developmental language disorder (DLD), it is natural for therapists to focus on the grammatical details of the target language that give the children special difficulty. However, along with the language-specific features of the target (e.g., for English, add -s to verbs in present tense, third-person singular contexts), there are overarching factors that operate to render the children's learning task more, or less, challenging, depending on the particular target.

AIMS

To identify five such factors that can play a role in the grammatical learning of children with DLD. We use English as our example language and provide supporting evidence from a variety of other languages.

MAIN CONTRIBUTION

We show that the relative degree of English-speaking children's difficulty with particular grammatical details can be affected by the extent to which these details involve: (1) bare stems; (2) opportunities for grammatical case confusion; (3) prosodic challenges; (4) grammatical and lexical aspect; and (5) deviations from canonical word order.

CONCLUSIONS

During treatment, therapists will want to consider not only the English-specific features of grammatical targets but also how these more general factors can be taken into account to increase the children's success.

Effects of a Complexity-Based Approach on Generalization of Past Tense -ed and Related Morphemes

Purpose

In a previous article, we reported that beginning treatment for regular past tense -ed with certain types of verbs led to greater generalization in children with developmental language disorder than beginning treatment with other types of verbs. This article provides updated data from that study, including the addition of data from 3 children, results from naturalistic language samples, and data from a third time point.

Method

Twenty 4- to 9-year-old children with developmental language disorder (10 per condition) were randomly assigned to receive language intervention in which the verbs used to teach regular past tense -ed were manipulated. Half received easy first intervention, beginning with highly frequent, telic, phonologically simple verbs, and half received hard first intervention, beginning with less frequent, atelic, and phonologically complex verbs. The design used a train-to-criterion approach, with children receiving up to 36 visits. Performance was assessed using elicited production probes and language samples before intervention, immediately following intervention and 6-8 weeks later.

Results

Children in the hard first group showed greater gains on the use of regular past tense -ed in both structured probes (at immediate post only) and in language samples (at both immediate and delayed post). Gains attributable to therapy were not observed in untreated morphemes.

Conclusions

This study suggests that the choice of therapy materials, with an eye on the role that treatment stimuli play in generalization, is important for treatment efficacy. Clinicians should consider early selection of atelic, lower-frequency, phonologically complex verbs when teaching children to use regular past tense -ed. Further work expanding this to other morphemes and a larger population is needed to confirm this finding.

Realisation of grammatical morphemes by children with phonological impairment

The aim of this research was to explore how preschool-aged children with phonological impairment (PI) realise grammatical morphemes across different phonological contexts (i.e. singleton consonant, consonant cluster, syllable), conditions of finiteness and individual morpheme types. Factors accounting for children's realisation of grammatical morphemes were also examined. Eighty-seven Australian English-speaking preschoolers (aged 4-5 years) with PI completed the Children's Assessment of Morphophonology (CHAMP)-an elicited response task-in addition to standardised tests of speech and receptive language. The most challenging grammatical morphemes were finite morphemes (particularly past tense) and grammatical morphemes realised in consonant clusters. The ability to produce consonant clusters in single words significantly accounted for children's ability to realise grammatical morphemes, regardless of whether grammatical morphemes were realised in singleton, consonant cluster or syllable contexts. Realisation of grammatical morphemes by preschoolers with PI is influenced by phonological and morphological factors. The findings have implications regarding the assessment and differential diagnosis of preschoolers with concomitant phonological and language difficulties.

Do the Hard Things First: A Randomized Controlled Trial Testing the Effects of Exemplar Selection on Generalization Following Therapy for Grammatical Morphology

PURPOSE

Complexity-based approaches to treatment have been gaining popularity in domains such as phonology and aphasia but have not yet been tested in child morphological acquisition. In this study, we examined whether beginning treatment with easier-to-inflect (easy first) or harder-to-inflect (hard first) verbs led to greater progress in the production of regular past-tense -ed by children with developmental language disorder.

METHOD

Eighteen children with developmental language disorder (ages 4-10) participated in a randomized controlled trial (easy first, N = 10, hard first, N = 8). Verbs were selected on the basis of frequency, phonological complexity, and telicity (i.e., the completedness of the event). Progress was measured by the duration of therapy, number of verb lists trained to criterion, and pre/post gains in accuracy for trained and untrained verbs on structured probes.

RESULTS

The hard-first group made greater gains in accuracy on both trained and untrained verbs but did not have fewer therapy visits or train to criterion on more verb lists than the easy-first group. Treatment fidelity, average recasts per session, and verbs learned did not differ across conditions.

CONCLUSION

When targeting grammatical morphemes, it may be most efficient for clinicians to select harder rather than easier exemplars of the target.

Influences of Phonological Context on Tense Marking in Spanish-English Dual Language Learners

PURPOSE

The emergence of tense-morpheme marking during language acquisition is highly variable, which confounds the use of tense marking as a diagnostic indicator of language impairment in linguistically diverse populations. In this study, we seek to better understand tense-marking patterns in young bilingual children by comparing phonological influences on marking of 2 word-final tense morphemes.

METHOD

In spontaneous connected speech samples from 10 Spanish-English dual language learners aged 56-66 months (M = 61.7, SD = 3.4), we examined marking rates of past tense -ed and third person singular -s morphemes in different environments, using multiple measures of phonological context.

RESULTS

Both morphemes were found to exhibit notably contrastive marking patterns in some contexts. Each was most sensitive to a different combination of phonological influences in the verb stem and the following word.

CONCLUSIONS

These findings extend existing evidence from monolingual speakers for the influence of word-final phonological context on morpheme production to a bilingual population. Further, novel findings not yet attested in previous research support an expanded consideration of phonological context in clinical decision making and future research related to word-final morphology.