Semantic fluency difficulties in developmental dyslexia and developmental language disorder (DLD): poor semantic structure of the lexicon or slower retrieval processes?

BACKGROUND: Children with dyslexia and/or developmental language disorder (hereafter children with DDLD) have been reported to retrieve fewer words than their typically developing (TD) peers in semantic fluency tasks. It is not known whether this retrieval difficulty can be attributed to the semantic structure of their lexicon being poor or, alternatively, to words being retrieved more slowly despite semantic structure being intact. AIMS: To test two theoretical models that could potentially account for retrieval difficulties in semantic fluency tasks, namely, the Poor Lexical-Semantic Structure Model and the Slow-Retrieval Model. Both models predict that children with DDLD will retrieve fewer items compared with TD children. However, while the Poor Lexical-Semantic Structure Model predicts a less sophisticated network of semantic connections between words in the lexicon, as evidenced by smaller clusters of related items in children with DDLD, the Slow-Retrieval Model predicts intact inter-item associations in the lexicon, as evidenced by the two groups' clusters being of a similar size. The groups' semantic fluency performance was therefore compared. How semantic fluency performance related to children's language, literacy, and phonological skills was also investigated. METHODS & PROCEDURES: A total of 66 children with DDLD aged 7-12 years and 83 TD children aged 6-12 years, all monolingual Greek speakers, were tested on semantic fluency, using the categories 'animals', 'foods' and 'objects from around the house'. The numbers of correct and incorrect responses, clusters and switches, and the average cluster size were computed. Children were also assessed on non-verbal IQ, language, literacy and phonological tasks. OUTCOMES & RESULTS: In both groups, productivity in semantic fluency tasks correlated strongly with the numbers of clusters and switches, but not with average cluster size. The DDLD group produced significantly fewer correct responses and fewer clusters compared with the TD group, but the two groups showed similar switching and average cluster size. Children's language, literacy and phonological skills significantly predicted the number of correct responses produced, beyond the significant effect of age. CONCLUSIONS & IMPLICATIONS: We conclude that poorer semantic fluency performance in children with DDLD results not from a lexicon with poor semantic structure, but rather from slower retrieval processes from a lexicon with intact semantic structure. The underlying causes of slow lexical retrieval still need further investigation.

Sign-Supported English: is it effective at teaching vocabulary to young children with English as an Additional Language?

BACKGROUND: Children who are learning English as an Additional Language (EAL) may start school with smaller vocabularies than their monolingual peers. Given the links between vocabulary and academic achievement, it is important to evaluate interventions that are designed to support vocabulary learning in this group of children. AIMS: To evaluate an intervention, namely Sign-Supported English (SSE), which uses conventionalized manual gestures alongside spoken words to support the learning of English vocabulary by children with EAL. Specifically, the paper investigates whether SSE has a positive impact on Reception class children's vocabulary development over and above English-only input, as measured over a 6-month period. METHODS & PROCEDURES: A total of 104 children aged 4-5 years were recruited from two neighbouring schools in a borough of Outer London. A subset of 66 had EAL. In one school, the teachers used SSE, and in the other school they did not. Pupils in each school were tested at two time points (the beginning of terms 1 and 3) using three different assessments of vocabulary. Classroom-based observations of the teachers' and pupils' manual communication were also carried out. OUTCOMES & RESULTS: Results of the vocabulary assessments revealed that using SSE had no effect on how well children with EAL learnt English vocabulary: EAL pupils from the SSE school did not learn more words than EAL pupils at the comparison school. SSE was used in almost half of the teachers' observations in the SSE school, while spontaneous gestures were used with similar frequency by teachers in the comparison school. CONCLUSIONS & IMPLICATIONS: There are alternative explanations for the results. The first is that the use of signs alongside spoken English does not help EAL children of this age to learn words. Alternatively, SSE does have an effect, but we were unable to detect it because (1) teachers in the comparison school used very rich natural gesture and/or (2) teachers in the SSE school did not know enough BSL and this inhibited their use of spontaneous gesture. Explanations (1) and (2) might mean that the potential benefits of spontaneous gesture in the input to the children in the comparison school matched any potential benefits of SSE. We suggest that studying early years professionals' spontaneous use of gesture, and how their gesture supports the language learning of all children in their class, would be fruitful areas of research for the future.

Measurement Issues: Assessing language skills in young children.

BACKGROUND: Language and communication skills are central to children's ability to engage in social relationships and access learning experiences. This paper identifies issues which practitioners and researchers should consider when assessing language skills. A range of current language assessments is reviewed. KEY FINDINGS: Current screening measures do not meet psychometric prerequisites to identify language problems. There are significant challenges in the interpretation of language assessments, where socioeconomic status, language status and dialect, hearing impairment and test characteristics impact results. CONCLUSIONS: Psychometrically sound assessments of language are an essential component of developing effective and efficient interventions. The language trajectories of preschool children vary substantially; current screening measures have significant limitations. Composite measures of language performance are better indicators of language problems and disorders than single measures of component skills.

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.

Lexical organization in deaf children who use British Sign Language: evidence from a semantic fluency task.

We adapted the semantic fluency task into British Sign Language (BSL). In Study 1, we present data from twenty-two deaf signers aged four to fifteen. We show that the same 'cognitive signatures' that characterize this task in spoken languages are also present in deaf children, for example, the semantic clustering of responses. In Study 2, we present data from thirteen deaf children with Specific Language Impairment (SLI) in BSL, in comparison to a subset of children from Study 1 matched for age and BSL exposure. The two groups' results were comparable in most respects. However, the group with SLI made occasional word-finding errors and gave fewer responses in the first 15 seconds. We conclude that deaf children with SLI do not differ from their controls in terms of the semantic organization of the BSL lexicon, but that they access signs less efficiently.

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 children's performance. We therefore propose that the SASIT-E32 might prove to be a valuable tool in identifying SLI in bilingual children.

Neural correlates of sublexical processing in phonological working memory.

This study investigated links between working memory and speech processing systems. We used delayed pseudoword repetition in fMRI to investigate the neural correlates of sublexical structure in phonological working memory (pWM). We orthogonally varied the number of syllables and consonant clusters in auditory pseudowords and measured the neural responses to these manipulations under conditions of covert rehearsal (Experiment 1). A left-dominant network of temporal and motor cortex showed increased activity for longer items, with motor cortex only showing greater activity concomitant with adding consonant clusters. An individual-differences analysis revealed a significant positive relationship between activity in the angular gyrus and the hippocampus, and accuracy on pseudoword repetition. As models of pWM stipulate that its neural correlates should be activated during both perception and production/rehearsal [Buchsbaum, B. R., & D'Esposito, M. The search for the phonological store: From loop to convolution. Journal of Cognitive Neuroscience, 20, 762-778, 2008; Jacquemot, C., & Scott, S. K. What is the relationship between phonological short-term memory and speech processing? Trends in Cognitive Sciences, 10, 480-486, 2006; Baddeley, A. D., & Hitch, G. Working memory. In G. H. Bower (Ed.), The psychology of learning and motivation: Advances in research and theory (Vol. 8, pp. 47-89). New York: Academic Press, 1974], we further assessed the effects of the two factors in a separate passive listening experiment (Experiment 2). In this experiment, the effect of the number of syllables was concentrated in posterior-medial regions of the supratemporal plane bilaterally, although there was no evidence of a significant response to added clusters. Taken together, the results identify the planum temporale as a key region in pWM; within this region, representations are likely to take the form of auditory or audiomotor "templates" or "chunks" at the level of the syllable [Papoutsi, M., de Zwart, J. A., Jansma, J. M., Pickering, M. J., Bednar, J. A., & Horwitz, B. From phonemes to articulatory codes: an fMRI study of the role of Broca's area in speech production. Cerebral Cortex, 19, 2156-2165, 2009; Warren, J. E., Wise, R. J. S., & Warren, J. D. Sounds do-able: auditory-motor transformations and the posterior temporal plane. Trends in Neurosciences, 28, 636-643, 2005; Griffiths, T. D., & Warren, J. D. The planum temporale as a computational hub. Trends in Neurosciences, 25, 348-353, 2002], whereas more lateral structures on the STG may deal with phonetic analysis of the auditory input [Hickok, G. The functional neuroanatomy of language. Physics of Life Reviews, 6, 121-143, 2009].

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 children's 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 children's ability to reject alternative phonological forms seems to be primarily limited by their vocabulary size and phonological awareness abilities.

Parent-Child Interaction Therapy (PCIT) in school-aged children with specific language impairment.

BACKGROUND: Parents play a critical role in their child's language development. Therefore, advising parents of a child with language difficulties on how to facilitate their child's language might benefit the child. Parent-Child Interaction Therapy (PCIT) has been developed specifically for this purpose. In PCIT, the speech-and-language therapist (SLT) works collaboratively with parents, altering interaction styles to make interaction more appropriate to their child's level of communicative needs. AIMS: This study investigates the effectiveness of PCIT in 8-10-year-old children with specific language impairment (SLI) in the expressive domain. It aimed to identify whether PCIT had any significant impact on the following communication parameters of the child: verbal initiations, verbal and non-verbal responses, mean length of utterance (MLU), and proportion of child-to-parent utterances. METHODS & PROCEDURES: Sixteen children with SLI and their parents were randomly assigned to two groups: treated or delayed treatment (control). The treated group took part in PCIT over a 4-week block, and then returned to the clinic for a final session after a 6-week consolidation period with no input from the therapist. The treated and control group were assessed in terms of the different communication parameters at three time points: pre-therapy, post-therapy (after the 4-week block) and at the final session (after the consolidation period), through video analysis. It was hypothesized that all communication parameters would significantly increase in the treated group over time and that no significant differences would be found in the control group. OUTCOMES & RESULTS: All the children in the treated group made language gains during spontaneous interactions with their parents. In comparison with the control group, PCIT had a positive effect on three of the five communication parameters: verbal initiations, MLU and the proportion of child-to-parent utterances. There was a marginal effect on verbal responses, and a trend towards such an effect for non-verbal responses. CONCLUSIONS & IMPLICATIONS: Despite the small group sizes, this study provides preliminary evidence that PCIT can achieve its treatment goals with 8-10-year-olds who have expressive language impairments. This has potentially important implications for how mainstream speech and language services provide intervention to school-aged children. In contrast to direct one-to-one therapy, PCIT offers a single block of therapy where the parents' communication and interaction skills are developed to provide the child with an appropriate language-rich environment, which in turn could be more cost-effective for the service provider.

Who did Buzz see someone? Grammaticality judgement of wh-questions in typically developing children and children with Grammatical-SLI.

This paper tests claims that children with Grammatical(G)-SLI are impaired in hierarchical structural dependencies at the clause level and in whatever underlies such dependencies with respect to movement, chain formation and feature checking; that is, their impairment lies in the syntactic computational system itself (the Computational Grammatical Complexity hypothesis proposed by van der Lely in previous work). We use a grammaticality judgement task to test whether G-SLI children's errors in wh-questions are due to the hypothesised impairment in syntactic dependencies at the clause level or lie in more general processes outside the syntactic system, such as working memory capacity. We compare the performance of 14 G-SLI children (aged 10-17 years) with that of 36 younger language-matched controls (aged 5-8 years). We presented matrix wh-subject and object questions balanced for wh-words (who/what/which) that were grammatical, ungrammatical, or semantically inappropriate. Ungrammatical questions contained wh-trace or T-to-C dependency violations that G-SLI children had previously produced in elicitation tasks. G-SLI children, like their language controls, correctly accepted grammatical questions, but rejected semantically inappropriate ones. However, they were significantly impaired in rejecting wh-trace and T-to-C dependency violations. The findings provide further support for the CGC hypothesis that G-SLI children have a core deficit in the computational system itself that affects syntactic dependencies at the clause level.

Developmental disorders of language and literacy: special issue.

Language and literacy are cognitive skills of exceptional complexity. It is therefore not surprising that they are at risk of impairment either during development or as a result of damage (e.g. stroke) later in life. Impaired language and literacy can arise from a general learning impairment. However, two developmental disorders, specific language impairment (SLI) and dyslexia, which affect oral and written language, respectively, are 'specific' in that they are not part of a more general learning difficulty. SLI and dyslexia each affect 5-10% of the general population, and they are the focus of the papers in this special issue.

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 Spelling Errors of French and English Children With Developmental Language Disorder at the End of Primary School.

Children with Developmental Language Disorder (DLD) often struggle learning to spell. However, it is still unclear where their spelling difficulties lie, and whether they reflect on-going difficulties with specific linguistic domains. It is also unclear whether the spelling profiles of these children vary in different orthographies. The present study compares the spelling profiles of monolingual children with DLD in France and England at the end of primary school. By contrasting these cohorts, we explored the linguistic constraints that affect spelling, beyond phono-graphemic transparency, in two opaque orthographies. Seventeen French and 17 English children with DLD were compared to typically developing children matched for age or spelling level. Participants wrote a 5 min sample of free writing and spelled 12 controlled dictated words. Spelling errors were analyzed to capture areas of difficulty in each language, in the phonological, morphological, orthographic and semantic domains. Overall, the nature of the errors produced by children with DLD is representative of their spelling level in both languages. However, areas of difficulty vary with the language and task, with more morphological errors in French than in English across both tasks and more orthographic errors in English than in French dictated words. The error types produced by children with DLD also differed in the two languages: segmentation and contraction errors were found in French, whilst morphological ending errors were found in English. It is hypothesized that these differences reflect the phonological salience of the units misspelled in both languages. The present study also provides a detailed breakdown of the spelling errors found in both languages for children with DLD and typical peers aged 5-11.

Deficient Explicit Access to Phonological Representations Explains Phonological Fluency Difficulties in Greek Children With Dyslexia and/or Developmental Language Disorder.

It is well-established that children with dyslexia and/or Developmental Language Disorder (hereafter children with DDLD) perform poorly on phonological tasks compared to typically developing (TD) children. However, there has been some debate as to whether their phonological deficit arises directly from an impairment in phonological representations, or instead from deficient access to (intact) phonological representations. This study tested the Degraded Phonological Representations Hypothesis and the Deficient Phonological Access Hypothesis using a task that is not often used with children with DDLD, namely phonological fluency. Both hypotheses predict that children with DDLD will retrieve fewer items than their TD peers in the phonological fluency task. However, while the Degraded Phonological Representations Hypothesis predicts smaller clusters of phonologically related items in children with DDLD, the Deficient Phonological Access Hypothesis predicts that the two groups will not differ in cluster size. How phonological fluency performance related to children's language, literacy, and phonological skills was investigated. Further, the specificity of a phonological fluency deficit in children with DDLD was tested using a nonverbal (design) fluency task. Sixty-six children with DDLD aged 7-12 years and 83 TD children aged 6-12 years, all monolingual Greek speakers, were tested on three phonological fluency categories, on nonverbal IQ, language, literacy, and phonological tasks, and on a design fluency task. The DDLD group produced significantly fewer correct responses and fewer switches compared to the TD group, but the two groups showed similar clustering and average cluster size. After controlling for age, children's language, literacy, and phonological skills significantly predicted the number of correct responses produced. The two groups did not differ significantly on the number of unique designs generated in the design fluency task. Furthermore, children with DDLD showed poorer phonological fluency performance relative to their TD peers even after design fluency performance was controlled, demonstrating the specificity of their phonological fluency deficit. This study adds to the theoretical debate on the locus of the phonological deficit in dyslexia and DLD. The findings support the hypothesis that the phonological deficit in dyslexia and DLD lies in deficient explicit access to intact phonological representations.

Using the Hands to Represent Objects in Space: Gesture as a Substrate for Signed Language Acquisition.

An ongoing issue of interest in second language research concerns what transfers from a speaker's first language to their second. For learners of a sign language, gesture is a potential substrate for transfer. Our study provides a novel test of gestural production by eliciting silent gesture from novices in a controlled environment. We focus on spatial relationships, which in sign languages are represented in a very iconic way using the hands, and which one might therefore predict to be easy for adult learners to acquire. However, a previous study by Marshall and Morgan (2015) revealed that this was only partly the case: in a task that required them to express the relative locations of objects, hearing adult learners of British Sign Language (BSL) could represent objects' locations and orientations correctly, but had difficulty selecting the correct handshapes to represent the objects themselves. If hearing adults are indeed drawing upon their gestural resources when learning sign languages, then their difficulties may have stemmed from their having in manual gesture only a limited repertoire of handshapes to draw upon, or, alternatively, from having too broad a repertoire. If the first hypothesis is correct, the challenge for learners is to extend their handshape repertoire, but if the second is correct, the challenge is instead to narrow down to the handshapes appropriate for that particular sign language. 30 sign-naïve hearing adults were tested on Marshall and Morgan's task. All used some handshapes that were different from those used by native BSL signers and learners, and the set of handshapes used by the group as a whole was larger than that employed by native signers and learners. Our findings suggest that a key challenge when learning to express locative relations might be reducing from a very large set of gestural resources, rather than supplementing a restricted one, in order to converge on the conventionalized classifier system that forms part of the grammar of the language being learned.

A challenge to current models of past tense inflection: the impact of phonotactics.

Is past tense production better modelled by a Single Mechanism or a Words and Rules model? We present data concerning a phenomenon that has not been considered by either model-regular past tense verbs with contrasting phonotactics. One set of verbs contains clusters at the inflected verb end that also occur in monomorphemic words ('monomorphemically legal clusters', MLC) whereas the other has clusters that can only occur in inflected forms ('monomorphemically illegal clusters', MIC). We argue that if children apply a morphological rule, phonotactics will not affect performance. Conversely, if children store past tense forms, they will perform better on verbs with MLCs because these clusters are more frequent. We investigated three populations--typically developing children, Grammatical-SLI (G-SLI) and Williams Syndrome (WS)--using past tense elicitation tasks. In Experiment 1 we reanalyse data from van der Lely and Ullman [van der Lely, H. K. J. & Ullman, M. (2001). Past tense morphology in specifically language impaired and normally developing children. Language and Cognitive Processes, 16: 177-217] and show that G-SLI children perform better on MLC verbs, whereas for typically developing children phonotactics do not affect performance. In Experiment 2 we replicate these findings in new groups of G-SLI and typically developing children. In Experiment 3 we reanalyse data from Thomas et al. [Thomas, M. S. C., Grant, J., Barham, Z., Gsodl, M., Laing, E., Lakusta, L., Tyler, L.K., Grice, S., Paterson, S. & Karmiloff-Smith, A. (2001) Past tense formation in Williams Syndrome. Language and Cognitive Processes, 16: 143-176] and show that phonotactics do not affect performance in individuals with WS. We argue that the results elucidate the underlying nature of morphology in these populations, and are better accommodated within a Words and Rules model of past tense acquisition.

Teachers' reported practices for teaching writing in England.

To date there have been no systematic studies examining the ways in which teachers in England focus and adapt their teaching of writing. The current study addresses this gap by investigating the nature and frequency of teachers' approaches to the teaching of writing in a sample of English primary schools, using the 'simple view of writing' as a framework to examine the extent to which different aspects of the writing process are addressed. One hundred and eighty-eight staff from ten different schools responded to an online questionnaire. Only the data from class teachers (n = 88) who responded to all items on the questionnaire were included in the final analyses. Respondents enjoyed teaching writing and felt prepared to teach it. However, despite feeling that they were effective in identifying approaches to support students' writing, nearly half reported that supporting struggling writers was problematic for them. Overall teachers reported more work at word level, occurring several times a week, than with transcription, sentence or text levels, which were reported to occur weekly. Planning, reviewing and revising occurred least often, only monthly. For these variables no differences were found between teachers of younger (age 4-7) and older students (age 8-11). By contrast, an examination of specific aspects of each component revealed differences between the teachers of the two age groups. Teachers of younger students focused more frequently on phonic activities related to spelling, whereas teachers of older students focussed more on word roots, punctuation, word classes and the grammatical function of words, sentence-level work, and paragraph construction.

From gesture to sign language: conventionalization of classifier constructions by adult hearing learners of British Sign Language.

There has long been interest in why languages are shaped the way they are, and in the relationship between sign language and gesture. In sign languages, entity classifiers are handshapes that encode how objects move, how they are located relative to one another, and how multiple objects of the same type are distributed in space. Previous studies have shown that hearing adults who are asked to use only manual gestures to describe how objects move in space will use gestures that bear some similarities to classifiers. We investigated how accurately hearing adults, who had been learning British Sign Language (BSL) for 1-3 years, produce and comprehend classifiers in (static) locative and distributive constructions. In a production task, learners of BSL knew that they could use their hands to represent objects, but they had difficulty choosing the same, conventionalized, handshapes as native signers. They were, however, highly accurate at encoding location and orientation information. Learners therefore show the same pattern found in sign-naïve gesturers. In contrast, handshape, orientation, and location were comprehended with equal (high) accuracy, and testing a group of sign-naïve adults showed that they too were able to understand classifiers with higher than chance accuracy. We conclude that adult learners of BSL bring their visuo-spatial knowledge and gestural abilities to the tasks of understanding and producing constructions that contain entity classifiers. We speculate that investigating the time course of adult sign language acquisition might shed light on how gesture became (and, indeed, becomes) conventionalized during the genesis of sign languages.

Word production errors in children with developmental language impairments.

This review focuses on the errors that children with developmental language impairments make on three types of word production tasks: lexical retrieval, the elicitation of derivationally complex forms and the repetition of non-sense forms. The studies discussed in this review come principally from children with specific language impairment, and from children who are English-speakers or deaf users of British sign language. It is argued that models of word production need to be able to account for the data presented here, and need to have explanatory power across both modalities (i.e. speech and sign).

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.