What we can learn from naming errors of children with language impairment at preschool age

Atypical phonological processes in naming errors of children with language impairment

The current study explored the characteristics of phonological errors of preschool children with DLD (Developmental Language Disorder), distinguishing between typical versus atypical phonological processes in segmental, syllabic and word levels. The analysis included 87 responses of words with phonological errors from a naming test, produced by 13 preschool children with DLD, aged 4;4-6;3 years. These responses included 166 phonological processes, which were classified into typical and atypical processes at the levels of: segments, syllables, and prosodic words. The findings revealed that 70% of the phonological processes were atypical. Furthermore, ten children produced more atypical processes, and there were more atypical than typical processes in segmental and word levels. It is suggested that some children with DLD represent phonological processes that are similar to those that children with speech and sound disorders produce. Therefore, clinically, the results emphasise the importance of analysing the typical and atypical characteristics of phonological errors as part of language assessment.

An access deficit or a deficit in the phonological representations themselves: What can we learn from naming errors?

Anomic aphasia is characterized by good comprehension and non-word repetition but poor naming. Two sub-types of deficits might be hypothesized: faulty access to preserved phonological representations or preserved access to impaired representations. Phonological errors may occur only when representations are impaired or in post-lexical deficits (conduction aphasia). We analysed the incidence of phonological naming errors of 30 individuals, 25 with anomic aphasia based on poor naming but good repetition and comprehension, and five with conduction aphasia based on poor naming and poor repetition. Individuals with anomic aphasia produced very few phonological errors compared to individuals with conduction aphasia (0-19.1% versus 42-66%). However, six individuals with anomia produced more than 11% phonological errors, suggesting two patterns of deficit: either impaired lexical representations or impaired access to them. The lack of phonological errors in most individuals with anomic aphasia suggests that access to the phonological output lexicon is semantically, not phonologically driven.

Phonological Priming as a Lens for Phonological Organization in Children With Cochlear Implants

OBJECTIVES

To evaluate the subconscious knowledge of between-word phonological similarities in children with cochlear implants as compared with children with typical hearing.

DESIGN

Participants included 30 children with cochlear implants between the ages of five and seven who used primarily spoken English to communicate, 30 children matched for chronological age, and 30 children matched for vocabulary size. Participants completed an animacy judgment task in either a (a) neutral condition, (b) a phonological prime condition where the consonant and vowel onset of the pictured word was presented prior to the visual target's appearance, (c) an inhibition prime condition where a consonant and vowel onset not matching the pictured word was presented prior to the target's appearance. Reaction times were recorded.

RESULTS

Children with cochlear implants reacted differently and more slowly than children with typical hearing in both groups to the primes: children with typical hearing experienced a phonological facilitation effect in the phonological prime condition, whereas children with cochlear implants did not. Children with cochlear implants also had reaction times that, overall, were slower than children matched for chronological age but similar to children matched for vocabulary size.

CONCLUSIONS

The different experience of children with cochlear implants with phonological facilitation and inhibition effects may indicate children with cochlear implants have phonological organization strategies that are different from those of children with typical hearing.

Modeling the Mental Lexicon as Part of Long-Term and Working Memory and Simulating Lexical Access in a Naming Task Including Semantic and Phonological Cues

BACKGROUND

To produce and understand words, humans access the mental lexicon. From a functional perspective, the long-term memory component of the mental lexicon is comprised of three levels: the concept level, the lemma level, and the phonological level. At each level, different kinds of word information are stored. Semantic as well as phonological cues can help to facilitate word access during a naming task, especially when neural dysfunctions are present. The processing corresponding to word access occurs in specific parts of working memory. Neural models for simulating speech processing help to uncover the complex relationships that exist between neural dysfunctions and corresponding behavioral patterns.

METHODS

The Neural Engineering Framework (NEF) and the Semantic Pointer Architecture (SPA) are used to develop a quantitative neural model of the mental lexicon and its access during speech processing. By simulating a picture-naming task (WWT 6-10), the influence of cues is investigated by introducing neural dysfunctions within the neural model at different levels of the mental lexicon.

RESULTS

First, the neural model is able to simulate the test behavior for normal children that exhibit no lexical dysfunction. Second, the model shows worse results in test performance as larger degrees of dysfunction are introduced. Third, if the severity of dysfunction is not too high, phonological and semantic cues are observed to lead to an increase in the number of correctly named words. Phonological cues are observed to be more effective than semantic cues.

CONCLUSION

Our simulation results are in line with human experimental data. Specifically, phonological cues seem not only to activate phonologically similar items within the phonological level. Moreover, phonological cues support higher-level processing during access of the mental lexicon. Thus, the neural model introduced in this paper offers a promising approach to modeling the mental lexicon, and to incorporating the mental lexicon into a complex model of language processing.

The joint effects of bilingualism, DLD and item frequency on children's lexical-retrieval performance

BACKGROUND

Bilingual children and children diagnosed with developmental language disorder (DLD) are characterized by reduced lexical-retrieval abilities. Few studies examined their joint contribution and the mechanisms underlying these effects in the lexical domain.

AIMS

To explore the joint effects of bilingualism and DLD by adopting a four-group comparison in which the difference between bi- and monolingual children with DLD is directly compared with that of bi- and monolingual children with typical language development (TLD). In addition, to examine the mechanisms underlying the effects of bilingualism and DLD on children's lexical-retrieval abilities, we tested how item's characteristics (frequency of use) modulate the effects of bilingualism and DLD.

METHODS & PROCEDURES

Fifty-eight children (aged 9-14 years) participated in the current study. They were either Hebrew monolingual or Hebrew-English bilinguals and were either diagnosed with DLD or had TLD. Children completed a Hebrew picture-naming task and verbal short-term memory tests. The influence of participants' characteristics, including bilingualism, DLD and verbal short-term memory, as well as item's characteristics (frequency of use) were tested.

OUTCOMES & RESULTS

Accuracy analysis revealed that bilingual children scored lower than monolingual children and that children with DLD scored lower than children with TLD. Critically, the two factors interacted such that their joint presence resulted in less-than-additive effects. Specifically, although bilingual children with DLD performed worse than all other groups, they performed better than expected under an additive model. Interestingly, monolingual children with DLD performed similarly to bilingual children with TLD. Increased verbal short-term memory was associated with better performance across the four groups. Finally, bilingualism and DLD interacted with item frequency, such that being bilingual, having DLD, or both, resulted in increased sensitivity to item frequency manifested in exceptionally lower performance on low-frequency items.

CONCLUSIONS & IMPLICATIONS

The findings suggest that the strength of linguistic representations contribute to the effects of bilingualism and DLD. Further, the presence of bilingualism in the context of DLD does not exaggerate the impact of DLD. Clinically, this suggests that differences between bi- and monolingual children with DLD must be considered in reference to the gap in lexical-retrieval performance observed between bi- and monolingual children with TLD. Finally, because monolingual children with DLD and bilingual children with TLD performed similarly, sensitive diagnostic tools and intervention programmes should be adopted to allow correct identification and treatment of bilingual children with DLD.