Language in genetic syndromes and cognitive modularity

In recent years, research into the impact of genetic abnormalities on cognitive development, including language, has become recognized for its potential to make valuable contributions to our understanding of the brain–behaviour relationships underlying language acquisition as well as to understanding the cognitive architecture of the human mind. The publication of Fodor’s ( 1983 ) book The Modularity of Mind has had a profound impact on the study of language and the cognitive architecture of the human mind. Its central claim is that many of the processes involved in comprehension are undertaken by special brain systems termed ‘modules’. This domain specificity of language or modularity has become a fundamental feature that differentiates competing theories and accounts of language acquisition (Fodor 1983 , 1985 ; Levy 1994 ; Karmiloff-Smith 1998 ). However, although the fact that the adult brain is modularized is hardly disputed, there are different views of how brain regions become specialized for specific functions. A question of some interest to theorists is whether the human brain is modularized from the outset (nativist view) or whether these distinct brain regions develop as a result of biological maturation and environmental input (neuroconstructivist view). One source of insight into these issues has been the study of developmental disorders, and in particular genetic syndromes, such as Williams syndrome (WS) and Down syndrome (DS). Because of their uneven profiles characterized by dissociations of different cognitive skills, these syndromes can help us address theoretically significant questions. Investigations into the linguistic and cognitive profiles of individuals with these genetic abnormalities have been used as evidence to advance theoretical views about innate modularity and the cognitive architecture of the human mind. The present chapter will be organized as follows. To begin, two different theoretical proposals in the modularity debate will be presented. Then studies of linguistic abilities in WS and in DS will be reviewed. Here, the emphasis will be mainly on WS due to the fact that theoretical debates have focused primarily on WS, there is a larger body of literature on WS, and DS subjects have typically been used for the purposes of comparison. Finally, the modularity debate will be revisited in light of the literature review of both WS and DS. Conclusions will be drawn regarding the contribution of these two genetic syndromes to the issue of cognitive modularity, and in particular innate modularity

Williams Syndrome, specific language impairment and modularity.

It has been widely claimed that the language abilities in individuals with Williams Syndrome (WS) provide evidence for dissociations between verbal and non-verbal cognitive processes, thereby supporting the modularity hypothesis. Although previous research has delineated a variety of skills and weaknesses in the WS profile, the reported results have been conflicting and inconsistent. It has also been claimed that WS is the 'opposite' of Specific Language Impairment (SLI), that is, that, in contrast to SLI, individuals with WS have relatively well preserved linguistic abilities in the face of cognitive deficits. However there have not been any studies that have directly compared the two populations on verbal and non-verbal tasks. The aims of the present thesis are: to investigate whether individuals with WS show superior verbal abilities in comparison to their non-verbal cognitive functioning; to investigate whether the individuals with WS show the 'opposite' profile to that of individuals with SLI; and to address the question of whether WS offers support for modular views of language. Case study series of five participants with WS and five participants with SLI were carried out. The study not only gathered information from a range of standardised verbal and non-verbal tests but, most importantly, combined these results with analysis of conversational interaction and narrative discourse, which has not been done previously. The results suggest there is a wide variability among individuals with WS (and those with SLI), and that the linguistic abilities of individuals with WS can often be severely impaired, sometimes being even inferior to those of children with SLI. Furthermore, there seems to be no statistically significant difference between the WS and the SLI profile with regard to their linguistic abilities, although the two profiles are clearly distinct regarding their non-verbal abilities. The results are discussed in light of the relevant literature and the current theoretical debates on modularity

Pitch range and vowel duration in the speech of children with Williams syndrome

This paper reports the pitch range and vowel duration data from a group of children with Williams syndrome (WS) in comparison with a group of typically developing children matched for chronological age (CA) and a group matched for receptive language abilities (LA). It is found that the speech of the WS group has a greater pitch range and that vowels tend to be longer in duration than in the speech of the typically developing children. These findings are in line with the impressionistic results reported by Reilly, Klima and Bellugi [17]

The perception of sentence stress in Malay and English

There is little research on stress and prominence in Bahasa Melayu (BM). Work which has been done on varieties of Malay concluded that pitch or durational differences do not contribute to the production or perception of stress. This study aimed to investigate the role of intensity in the perception of stress in BM among two groups of listeners, 16 native speakers of BM and 30 of BrE, in comparison with spoken British English (BrE) and Malay Speaker English (MSE). Listeners rated 30 low-pass filtered sentences, ten from each language, indicating all syllables they perceived as stressed. Comparisons of listener identification of stress with syllable intensity yielded no statistically significant difference in the BrE and MSE conditions. In the BM condition, BrE listeners rated significantly more syllables as stressed with low to mid intensity than the BM listeners. The results are discussed in terms of the contribution of intensity to perceived prominence in languages

The interplay of stress saliency and word beginning saliency: an experimental study

There is a robust amount of evidence (mostly from English) suggesting that, while listening to speech, the initial part of words is scrutinised with more attention. Similarly, data suggests that stressed syllables are processed with more precision than unstressed syllables. How do these two kinds of saliencies interact? In this experimental study, the issue was investigated in a group of Italian speakers. Participants were presented with minimal pairs of nonwords differing in one individual phoneme (and specifically one trait, voicing). Nonwords were created as to contain phonological clusters in either an initial or medial position, and, similarly, stress was placed in either initial or medial position. Results show that when the clusters were in word medial position, there was a large effect of stress, with stressed syllables being recognised with greater accuracy. When the clusters were in initial position, instead, accuracy was at an intermediate level and we did not observe any effect of stress. The result is discussed in relation to previous literature addressing these phenomena in English

Sensitivity to inflectional morphemes in the absence of meaning: evidence from a novel task

A number of studies in different languages have shown that speakers may be sensitive to the presence of inflectional morphology in the absence of verb meaning (Caramazza et al., 1988, Clahsen, 1999, Post et al., 2008). In this study, sensitivity to inflectional morphemes was tested in a purposely developed task with English-like nonwords. Native speakers of English were presented with pairs of nonwords and were asked to judge whether the two nonwords in each pair were the same or different. Each pair was composed either of the same nonword repeated twice, or of two slightly different nonwords. The nonwords were created taking advantage of a specific morphophonological property of English, which is that regular inflectional morphemes agree in voicing with the ending of the stem. Using stems ending in /l/, thus, we created: 1. nonwords ending in potential inflectional morphemes, vɔld, 2. nonwords without inflectional morphemes, vɔlt, and 3. a phonological control condition, vɔlb. Our new task endorses some strengths presented in previous work. As in Post et al. (2008) the task accounts for the importance of phonological cues to morphological processing. In addition, as in Caramazza et al. (1988) and contrary to Post et al. (2008), the task never presents bare-stems, making it unlikely that the participants would be aware of the manipulation performed. Our results are in line with Caramazza et al. (1988), Clahsen (1999) and Post et al. (2008), and offer further evidence that morphologically inflected nonwords take longer to be discriminated compared to uninflected nonwords

Longitudinal predictors of early language in infants with Down syndrome: a preliminary study

Purpose: Children with Down syndrome (DS) typically have marked delays in language development relative to their general cognitive development, with particular difficulties in expressive compared to receptive language. Although early social communication skills, including gestures and joint attention, have been shown to be related to later language outcomes in DS, knowledge is limited as to whether these factors exclusively predict outcomes, or whether other factors (e.g. perceptual and non-verbal skills) are involved. This study addressed this question. Method: Longitudinal data for a group of infants with DS (n=14) and a group of typically-developing (TD) infants (n=35) were collected on measures that have been shown to predict language in TD infants and/or those with developmental delays. These included: non-verbal mental ability, speech segmentation skills, and early social communication skills (initiating and responding to joint attention, initiating behavioural requests). Results: Linear regression analyses showed that speech segmentation and initiating joint attention were the strongest predictors of later language in the TD group, whereas non-verbal mental ability and responding to joint attention were the strongest predictors of later language for infants with DS. Conclusions: Speech segmentation ability may not determine language outcomes in DS, and language acquisition may be more constrained by social communication and general cognitive skills

Sentence repetition as a clinical marker of developmental language disorder: evidence from Arabic

Purpose: Research on the typical and impaired grammatical acquisition of Arabic is limited. This study systematically examined the morpho-syntactic abilities of Arabic-speaking children with and without Developmental Language Disorder (DLD) using a novel sentence repetition task. The usefulness of the task as an indicator of DLD in Arabic was determined. Methods: A sentence repetition task was developed in Palestinian Arabic (LITMUS-SR-PA-72) and administered to 30 children with DLD (M = 61.50 months, SD = 11.27) and 60 age-matched TD children (M = 63.85 months, SD = 10.16).The task targeted grammatical structures known to be problematic for Arabic-speaking children with DLD (language-specific) and children with DLD across languages (language-independent). Responses were scored using binary, error and structural scoring methods. Results: Children with DLD scored below TD children on the LITMUS-SR-PA-72 in general as well as in the repetition of language-specific and language-independent structures. The frequency of morpho-syntactic errors was higher in the DLD group relative to the TD group. Despite the large similarity of the type of morpho-syntactic errors between the two groups, there were some atypical errors exclusively produced by the DLD group. The three scoring methods showed good diagnostic power in the discrimination between children with and without DLD. Conclusion: Sentence repetition was an area of difficulty for Palestinian Arabic-speaking children with DLD. The DLD group demonstrated difficulties with language-specific and language-independent structures, particularly complex sentences with non-canonical word order. Most grammatical errors made by the DLD group resembled those of the TD group and were mostly omissions or substitutions of grammatical affixes or omissions of function words. SR appears to hold promise as a good indicator for the presence or absence of DLD in Arabic. Further validation of these findings using population-based studies is warranted

Expressive verb morphology deficits in Arabic-speaking children with Developmental Language Disorder

Purpose This study investigated the production of tense and subject-verb agreement in Palestinian Arabic-speaking children with Developmental Language Disorder (DLD) in comparison to their typically developing peers (TD) in terms of (1) performance accuracy and (2) error patterns. Method Participants were 14 children with DLD aged 4;0 - 7;10 (years; months) and 32 TD children aged 3;0-8;0 (years; months) matched on non-verbal abilities. Children were asked to complete a picture-based verb elicitation task. The task was designed to measure the production accuracy of tense and subject-verb agreement inflections in Arabic. Results The DLD group scored significantly lower than the TD group on the verb elicitation task. The DLD group was significantly less accurate than the TD group in marking tense, specifically present tense. They were also less accurate in marking agreement in general, with specific difficulty in using feminine verb forms. The DLD and TD groups differed in their tense error patterns, but not in agreement error patterns. Conclusion The acquisition of verb morphology in Palestinian Arabic-speaking children with DLD appears to be delayed and possibly different from their TD peers. The DLD group found the production of marked verb forms more challenging than less marked ones. These results are discussed in light of the structural characteristics of Arabic. Future studies would need to include larger sample sizes, investigate other aspects of verb morphology, including both production and comprehension, include other language domains, and consider longitudinal designs to provide more in-depth knowledge of Arabic language acquisition

Deaf children with spoken language bilingualism: professional guidance to parents

13% of deaf children in the UK use more than one spoken language. Parents of deaf children from bilingual backgrounds must decide whether to communicate with their child using more than one spoken language, with or without a signed language(s) as well. As most deaf children are born to hearing parents with little or no knowledge of deafness, professional guidance received during this decision-making process is critical. This study examined the beliefs of professionals on the ability of a deaf child to acquire two spoken languages and the advice professionals give to parents considering spoken language bilingualism for their deaf child. 108 professionals who work with deaf children in the UK (50 Teachers of the Deaf [ToDs], 47 speech and language therapists [SLTs] and 11 audiologists) completed an online questionnaire between the 24th May 2019 and the 1st July 2019. Most participants believed deaf children can achieve spoken language bilingualism and would advise parents to speak in their home language, regardless of the parents’ English proficiency. However, audiologists were 11 times more likely than SLTs to report linguistic confusion, and ToDs at least 11 times more likely than SLTs to report reduced proficiency in English and the home language because of bilingualism. ToDs and SLTs were found to play a key role in bilingual parents’ decision-making process. Consequently, there is a need for specific training and interprofessional learning to ensure parents receive consistent evidence-based advice