Grounded in the biopsychosocial models of expressive language in autism spectrum disorder (ASD) and fragile X syndrome (FXS), this dissertation included two novel studies that examined the role of biological (i.e., physiology), psychological (i.e., autistic traits, anxiety symptoms, and child affect) and social (i.e., communication partner…

Writing is an essential element of literacy development, and language plays a central role in the composing process, including developing, organizing, and refining ideas. Language and writing are interconnected, making it paramount for educators to attend to the development of deaf students' language skills. In this quasi-experimental study, we…

Prior work has found links between consistency in toddler handedness for the fine motor skill role-differentiated bimanual manipulation (RDBM), and language development at 2 and 3 years of age. The current study investigated whether consistency in handedness from 18 to 24 months (N = 90) for RDBM predicts receptive and expressive language…

The present study investigates the relation between language environment and language delay in 63 British-English speaking children (19 typical talkers (TT), 22 late talkers (LT), and 22 late bloomers (LB) aged 13 to 18 months. Families audio recorded daily routines and marked the new words their child produced over a period of 6 months. To…

Language Instruction, especially teaching and learning English for specific purposes (ESP) with Computer-Assisted Language Learning (CALL) has grown in popularity for over a decade. Task-based Language Teaching (TBLT) is one of the appropriate teaching approaches used to make CALL more effective. This study attempts to develop, implement, and…

Purpose: The extant literature suggests that individual differences in speech perception can be linked to broad receptive language phenotype. For example, a recent study found that individuals with a smaller receptive vocabulary showed diminished lexically guided perceptual learning compared to individuals with a larger receptive vocabulary. Here,…

We examined the relation of morphological awareness with language and literacy skills, namely phonological awareness, orthographic awareness, vocabulary, word reading, spelling, text reading fluency, and reading comprehension. We also examined potential moderators of the relations (grade level, orthographic depth of language, receptive vs.…

Late language emergence (LLE) may result from genetic and environmental factors. Little is known about environmental factors in LLE in South Africa. The study describes the nature of differences in language functioning between toddlers with LLE and without LLE, and which factors were associated with LLE in a middle-income area in South Africa.…

Purpose: This study reexamines the claim that difficulty forming memories of words comprising uncommon sound sequences (i.e., low phonological neighborhood density words) is a determinant of delayed expressive vocabulary development (e.g., Stokes, 2014). Method: We modeled communicative development inventory data from (N = 442) 18-month-old…

The cross-categorical use of nouns and verbs poses a challenging problem to young language learners because they are known to be less willing to accept that a single form of a word be used for more than one linguistic purpose (e.g., one-form/one-function principle). The present study investigated whether children under 3 years of age are able to…

This study investigates the probable effect of a digital game-based vocabulary learning (DGBVL) task on the acquisition of some components of a word knowledge framework. In so doing, 124 Persian speakers (56 males and 68 females) were randomly assigned to either a control or an experimental group. The experimental group participants completed a…

Few interventions exist for school-aged minimally verbal children with autism spectrum disorder (ASD). Even though play skills are associated with children's production of language, few studies have focused on play for minimally verbal children. Fifty-eight minimally verbal children with ASD received a naturalistic developmental behavioral…

Purpose: Some boys with autism spectrum disorder (ASD) and boys with fragile X syndrome and a codiagnosis of ASD (FXS+ASD) have impairments in expressive grammatical abilities. The current study compared grammatical performance in these 2 groups of school-age boys. Method: Thirty-seven boys similar on mean length of utterance participated in the…

This study examined dual language learners' (DLLs n = 24) and English-only (EO n = 20) children's expressive and receptive language in kindergarten (M[subscript age] = 5.7 years) as well as the relation to peers' language use. Expressive language skills (vocabulary diversity, syntactic complexity) were measured in the fall, winter, and spring…

Purpose: This was an investigation of the dimensionality of oral and written language to test the hypothesis that a two-factor model with sound/word and sentence/discourse language levels would best fit language and literacy data for a population-based sample in the school-age years. Method: A stratified secondary data set of 1,500 participants…