Chloe Marshall

Phonological deficits in specific language impairment and developmental dyslexia: towards a multidimensional model

An on-going debate surrounds the relationship between specific language impairment and developmental dyslexia, in particular with respect to their phonological abilities. Are these distinct disorders? To what extent do they overlap? Which cognitive and linguistic profiles correspond to specific language impairment, dyslexia and comorbid cases? At least three different models have been proposed: the severity model, the additional deficit model and the component model. We address this issue by comparing children with specific language impairment only, those with dyslexia-only, those with specific language impairment and dyslexia and those with no impairment, using a broad test battery of language skills. We find that specific language impairment and dyslexia do not always co-occur, and that some children with specific language impairment do not have a phonological deficit. Using factor analysis, we find that language abilities across the four groups of children have at least three independent sources of variance: one for non-phonological language skills and two for distinct sets of phonological abilities (which we term phonological skills versus phonological representations). Furthermore, children with specific language impairment and dyslexia show partly distinct profiles of phonological deficit along these two dimensions. We conclude that a multiple-component model of language abilities best explains the relationship between specific language impairment and dyslexia and the different profiles of impairment that are observed.

The impact of phonological complexity on past tense inflection in children with Grammatical-SLI

English-speaking children with Specific Language Impairment (SLI) variably produce inflected and bare stem forms in obligatory past tense contexts. Researchers have not reached consensus as to whether the underlying deficit is morphosyntactic or morphophonological in nature. The Computational Grammatical Complexity (CGC) Hypothesis takes a different tack: it hypothesizes that for children with a particular form of SLI, Grammatical-SLI, the deficit is in representing linguistic structural complexity in at least three components of the computational grammatical system – syntax, morphology and phonology. Deficits in all these components are predicted to impact on regular past tense formation. The impact of syntactic and morphological complexity on G-SLI childrens realization of tense has been tested previously. Here we complete the picture by considering phonological effects on their production of regular past tense inflection. Using a past tense elicitation task where we manipulate the phonological complexity of the inflected verb end, we show that, as predicted, verb-end phonological complexity impacts on suffixation: G-SLI children are less likely to suffix stems when the inflected form ends in a consonant cluster. Typically developing controls show no such effect. The results of this study highlight the need to consider the independent contributions of language components to impaired and normal performance.

Identifying specific language impairment in deaf children acquiring British Sign Language: Implications for theory and practice

This paper presents the first ever group study of specific language impairment (SLI) in users of sign language. A group of 50 children were referred to the study by teachers and speech and language therapists. Individuals who fitted pre-determined criteria for SLI were then systematically assessed. Here, we describe in detail the performance of 13 signing deaf children aged 5-14 years on normed tests of British Sign Language (BSL) sentence comprehension, repetition of nonsense signs, expressive grammar and narrative skills, alongside tests of non-verbal intelligence and fine motor control. Results show these children to have a significant language delay compared to their peers matched for age and language experience. This impaired development cannot be explained by poor exposure to BSL, or by lower general cognitive, social, or motor abilities. As is the case for SLI in spoken languages, we find heterogeneity within the group in terms of which aspects of language are affected and the severity of the impairment. We discuss the implications of the existence of language impairments in a sign language for theories of SLI and clinical practice.

The Acquisition of Sign Language: The Impact of Phonetic Complexity on Phonology

Research into the effect of phonetic complexity on phonological acquisition has a long history in spoken languages. This paper considers the effect of phonetics on phonological development in a signed language. We report on an experiment in which nonword-repetition methodology was adapted so as to examine in a systematic way how phonetic complexity in two phonological parameters of signed languages — handshape and movement — affects the perception and articulation of signs. Ninety-one Deaf children aged 3–11 acquiring British Sign Language (BSL) and 46 hearing nonsigners aged 6–11 repeated a set of 40 nonsense signs. For Deaf children, repetition accuracy improved with age, correlated with wider BSL abilities, and was lowest for signs that were phonetically complex. Repetition accuracy was correlated with fine motor skills for the youngest children. Despite their lower repetition accuracy, the hearing group were similarly affected by phonetic complexity, suggesting that common visual and motoric factors are at play when processing linguistic information in the visuo-gestural modality.

Derivational morphology in children with Grammatical- Specific Language Impairment

Although it is well‐established that children with Specific Language Impairment characteristically optionally inflect forms that require tense and agreement marking, their abilities with regards to derivational suffixation are less well understood. In this paper we provide evidence from children with Grammatical‐Specific Language Impairment (G‐SLI) that derivational suffixes, unlike tense and agreement suffixes, are not omitted in elicitation tasks. We investigate two types of derivation – comparative/superlative formation and adjective‐from‐noun formation – and reveal that G‐SLI children supply these suffixes at high rates, equivalent to their language matched peers. Moreover, increasing the phonological or morphological complexity of the stimulus does not trigger suffix omission, although it results in non‐target forms that are not characteristic of typically developing children. We discuss what these results reveal about the nature of the deficit in G‐SLI within the context of three hypotheses of SLI: the Extended Optional Infinitive, Implicit Rule and Computational Grammatical Complexity Hypotheses.

Assessing Component Language Deficits in the Early Detection of Reading Difficulty Risk

This article focuses on some of the linguistic components that underlie letter-sound decoding skills and reading comprehension: specifically phonology, morphology, and syntax. Many children who have reading difficulties had language deficits that were detectable before they began reading. Early identification of language difficulties will therefore help identify children at risk of reading failure. Using a developmental psycholinguistic framework, the authors provide a model of how syntax, morphology, and phonology break down in children with language impairments. The article reports on a screening test of these language abilities for preschool or young school-aged children that identifies those at risk for literacy problems and in need of further assessment.

Do children with dyslexia and/or specific language impairment compensate for place assimilation? Insight into phonological grammar and representations

English speakers have to recognize, for example, that te[m] in te[m] pens is a form of ten, despite place assimilation of the nasal consonant. Children with dyslexia and specific language impairment (SLI) are commonly proposed to have a phonological deficit, and we investigate whether that deficit extends to place assimilation, as a way of probing phonological representations and phonological grammar. Children with SLI plus dyslexia, SLI only, and dyslexia only listened to sentences containing a target word in different assimilatory contexts—viable, unviable, and no change—and pressed a button to report hearing the target. The dyslexia-only group did not differ from age-matched controls, but the SLI groups showed more limited ability to accurately identify words within sentences. Once this factor was taken into account, the groups did not differ in their ability to compensate for assimilation. The results add to a growing body of evidence that phonological representations are not necessarily impaired in dyslexia. SLI childrens results suggest that they too are sensitive to this aspect of phonological grammar, but are more liberal in their acceptance of alternative phonological forms of words. Furthermore, these childrens ability to reject alternative phonological forms seems to be primarily limited by their vocabulary size and phonological awareness abilities.

Non-Word Repetition Impairment in Autism and Specific Language Impairment: Evidence for Distinct Underlying Cognitive Causes.

Language-impaired individuals with autism perform poorly on tests such as non-word repetition that are sensitive clinical markers of specific language impairment (SLI). This has fuelled the theory that language impairment in autism represents a co-morbid SLI. However, the underlying cause of these deficits may be different in each disorder. In a novel task, we manipulated non-word stimuli in three ways known to influence the repetition accuracy of children with SLI. Participants with SLI were affected differently by these manipulations to children with autism. Children with autism performed similarly to language-matched typical children in terms of levels and patterns of performance, and types of error made, suggesting that the underlying cognitive cause of non-word repetition deficits is different in each disorder.

Sentence repetition as a measure of morphosyntax in monolingual and bilingual children

Bilingual children are frequently misdiagnosed as having Specific Language Impairment (SLI). Misdiagnosis may be minimized by tests with high degrees of sensitivity and specificity. The current study used a new test, the School-Age Sentence Imitation Test-English 32 (SASIT-E32), to investigate sentence repetition in monolingual and bilingual children, and specifically to compare overall repetition accuracy and error patterns in the two groups. Eighteen English-speaking monolingual children (mean age = 8;8) and 18 Farsi-English bilingual children (8;2) participated. Monolingual children repeated sentences more accurately than bilingual children, but, once receptive vocabulary scores were taken into account, this group difference disappeared. However, the groups demonstrated a different pattern of errors, with the bilingual group producing a higher proportion of substitution and addition errors on function words compared to content words. The main error expected from children with SLI according to the existing literature, i.e. the omission of function words, did not characterize the bilingual childrens performance. We therefore propose that the SASIT-E32 might prove to be a valuable tool in identifying SLI in bilingual children.

The effect of dyslexia on information retrieval: A pilot study

Purpose – The purpose of this paper is to resolve a gap in the knowledge of how people with dyslexia interact with information retrieval (IR) systems, specifically an understanding of their information‐searching behaviour.Design/methodology/approach – The dyslexia cognitive profile is used to design a logging system, recording the difference between two sets of participants: dyslexic and control users. A standard Okapi interface is used – together with two standard TREC topics – in order to record the information searching behaviour of these users.Findings – Using the log data, the differences in information‐searching behaviour of control and dyslexic users, i.e. in the way the two groups interact with Okapi, are established and it also established that qualitative information collected (such as experience etc.) may not be able to account for these differences. Evidence from query variables was unable to distinguish between groups, but differences on topic for the same variables were recorded. Users who v...