On average, language and communication characteristics of individuals with Down syndrome (the most common genetic cause of intellectual disability) follow a consistent profile. Despite considerable individual variability, receptive language is typically stronger than expressive language, with particular challenges in phonology and syntax. We review the literature on language and literacy skills of individuals with Down syndrome, with emphasis on the areas of phonology, vocabulary, syntax, and pragmatics. We begin by describing the hearing, oral-motor, cognitive, social, and prelinguistic and early nonverbal communication characteristics of individuals with Down syndrome. We conclude with a discussion of clinical implications and research directions. KeywordsCommunication; Down syndrome; Language; Literacy; Neurodevelopmental Disorders; Speech Despite considerable individual variability, individuals with Down syndrome have a characteristic profile of language and communication strengths and difficulties. Receptive language is typically stronger than expressive language, with phonology, syntax, and some aspects of pragmatics presenting particular developmental challenges. In this article, we review the research on phonology, vocabulary, syntax, pragmatics, and literacy skills of individuals with Down syndrome. We focus on receptive and expressive language in individuals of all ages. We begin by describing several foundations of language and communication development, including hearing, oral-motor, cognitive, social, and prelinguistic and early nonverbal communication skills. We conclude by describing implications for practice and directions for research.Since Down syndrome is a genetic disorder, the following review is largely consistent with a categorical, medical model of language development. Accordingly, we aim to show how language and literacy competence may be affected by the cognitive-behavioral phenotype associated with a diagnosis of Down syndrome. However, we recognize the theoretical and practical importance of other prevalent models such as the social model, which stresses the role of social or environmental factors in language learning. Indeed, we consider social skills Send reprint requests to:

Background Fragile X syndrome (FXS) and Down syndrome (DS) are the two leading genetic causes of intellectual disability, and FXS is the most common known genetic condition associated with autism. Both FXS and DS are associated with significant language impairment, but little is known about expressive language across domains over time or the role of autism in language development in FXS. Aims To compare three domains of language production (vocabulary, syntax, and pragmatics) over time within and across groups of boys with FXS with and without autism spectrum disorder (FXS-ASD, FXS-O), boys with DS, and typically developing (TD) boys. Methods & Procedures Twenty-nine boys with FXS-O, 40 boys with FXS-ASD, 34 boys with DS, and 48 younger TD boys of similar nonverbal mental age living in the United States participated. The Antonyms, Syntax Construction, and Pragmatic Judgment subtests of the Comprehensive Assessment of Spoken Language were administered annually over three years. Outcomes & Results TD boys scored higher than all other groups on all three subtests, boys with FXS-O and FXS-ASD scored higher than boys with DS in Syntax Construction, and boys with FXS-O scored higher than boys with FXS-ASD in Pragmatic Judgment. Within-group patterns varied between groups. Overall the TD group showed significantly more change over time than all other groups. Conclusions & Implications Findings suggest that expressive language skills and growth across various domains are more impaired in boys with FXS and DS than would be expected based on nonverbal mental age, that for boys with DS syntax is more impaired than would be expected based on intellectual disability, and that autism status affects pragmatic language in boys with FXS. Findings suggest that language production across domains should be addressed during assessment and intervention for boys with FXS and boys with DS, with differing group profiles also suggesting potentially different areas of focus.

A B S T R A C TWhen two people talk about an object, they depend on joint attention, a prerequisite for setting up common ground in a conversational exchange.In this study, we analyze this process for parent and child, with data from 40 dyads, to show how adults initiate joint attention in talking to young children (mean ages 1; 6 and 3 ; 0). Adults first get their children's attention with a summons (e.g. Ready ?, See this ?), but cease using such forms once children give evidence of attending. Children signal their attention by looking at the target object, evidence used by the adults. Only at that point do adults begin to talk about the object. From then on, they use language and gesture to offer information about and maintain attention on the target. The techniques adults rely on are interactive : they establish joint attention and maintain it throughout the exchange.Even the most casual observation of conversation reveals that the participants rely on gaze and gesture as well as speech. In this paper, we examine a model of how gaze and gesture contribute to joint attention in parent-child exchanges. Our focus is on how adults get young children's attention at the start of an exchange and then maintain it. Attention is a prerequisite to any communicative exchange (Brinck, 2001). With it, each participant attends and is aware that the other is attending too (H.

Adults rely on both speech and gesture to provide children with information pertinent to new word meanings. Parents were videotaped introducing new objects to their children (aged 1;6 and 3;0). They introduce these objects in three phases: (1) they establish joint attention on an object; (2) they introduce a label for it; (3) they situate the object conceptually. Parents used labels and gestures to maintain attention on the object; with one-year-olds, they led with gestures to capture the children’s attention. They added supplementary information about objects only after labeling them, again with speech and gesture. They used indicating gestures (point, touch, tap) to identify the objects labeled, their parts, and their properties. They used demonstrating gestures (turning a truck wheel, opening salad tongs) to depict actions and functions they were describing in words. These procedures support children in their construction of meanings for new words.

Background Fragile X syndrome (FXS) is the most common inherited cause of intellectual disability, and the most common single gene disorder associated with autism. Language impairments in this disorder are well documented, but the nature and extent of syntactic impairments are still unclear. Aims To compare the performance of boys with FXS with and without autism spectrum disorder on measures of verb (VM) and noun (NM) morphosyntax with that of typically developing boys of similar non-verbal mental ages. Methods & Procedures Conversational samples were obtained from 33 boys with FXS with autism spectrum disorder (FXS-ASD), 35 boys with FXS and no ASD (FXS-O), and 46 typically developing boys (TD). Production of verbal and nominal morphosyntax was assessed separately in these two subdomains. A hierarchical linear model compared morphosyntactic scores in all groups after adjusting for non-verbal cognition, articulatory skill, and caregiver education. The model also tested interactions between group and morphosyntactic subdomain. Outcomes & Results Boys with FXS in both groups scored lower than the TD boys on both measures. The FXS-O and the FXS-ASD groups did not differ on either composite measure. All covariates were significantly related to morphosyntactic scores. Conclusions & Implications Part of the morphosyntactic impairment in FXS may be attributable to cognitive, environmental, and speech factors. However, it is clear that boys with FXS perform at levels lower than expected from differences in these extra-linguistic factors alone, across both the verb and the noun domains. Clinical interventions should therefore seek to address specific syntactic targets.