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Purpose: Children come to understand many words by the end of their 1st year of life, and yet, generally by 12 months, only a few words are said. In this study, we investigated which linguistic factors contribute to this comprehension--expression gap the most. Specifically, we asked the following: Are phonological neighborhood density, semantic neighborhood density, and word frequency (WF) significant predictors of the probability that words known (understood) by children would appear in their spoken lexicons? Method: Monosyllabic words in the active (understood and said) and passive (understood, not said) lexicons of 201 toddlers were extracted from the Dutch Communicative Development Inventory (Zink & Lejaegere, 2002) parentcompleted forms. A generalized linear mixed-effects model was applied to the data.Results: Phonological neighborhood density and WF were independently and significantly associated with whether or not a known word would be in children's spoken lexicons, but semantic neighborhood density was not. There were individual differences in the impact of WF on the probability that known words would be said. Conclusion: The novel findings reported here have 2 major implications. First, they indicate that the comprehension--expression gap exists partly because the phonological distributional properties of words determine how readily words can be phonologically encoded for word production. Second, there are likely subtle and complex individual differences in how and when the statistical properties of the ambient language impact on children's emerging lexicons that might best be explored via longitudinal sampling of word knowledge and use. [ABSTRACT FROM AUTHOR]

Purpose: This study aimed to gain more insight into the relation between vocabulary and reading acquisition by examining early growth trajectories in the vocabulary of children at family risk (FR) of dyslexia longitudinally. Method: The sample included 212 children from the Dutch Dyslexia Program with and without an FR. Parents reported on their children's receptive and expressive vocabulary size at ages 17, 23, 29, and 35 months using the Dutch MacArthur Communicative Development Inventories. Dyslexia status at the end of Grade 2 (8 years) rendered 3 groups: FR-dyslexic (n = 51), FR-nondyslexic (n = 92), and typically developing-nondyslexic (TD) children (n = 69). Results: Repeated measures analyses showed that FR-dyslexic children had lower receptive vocabulary scores from 23 months onward and lower expressive scores from 17 months onward than FR-nondyslexic children. Latent growth curve modeling showed lower initial growth rates in FR-dyslexic children, followed by partial recovery, indicating a delayed increase in receptive and expressive vocabulary. FR-nondyslexic and TD children did not differ. Conclusions: Early deficits in receptive and expressive vocabulary are associated with later reading. Early vocabulary growth of FR-dyslexic children is characterized by a delay but not deviance of growth. Vocabulary can be considered an additional risk factor for dyslexia. [ABSTRACT FROM AUTHOR]

Purpose: This study assessed whether a categorical speech perception (CP) deficit is associated with dyslexia or familial risk for dyslexia, by exploring a possible cascading relation from speech perception to phonology to reading and by identifying whether speech perception distinguishes familial risk (FR) children with dyslexia (FRD) from those without dyslexia (FRND). Method: Data were collected from 9-year-old FRD (n = 37) and FRND (n = 41) children and age-matched controls (n = 49) on CP identification and discrimination and on the phonological processing measures rapid automatized naming, phoneme awareness, and nonword repetition. Results: The FRD group performed more poorly on CP than the FRND and control groups. Findings on phonological processing align with the literature in that (a) phonological processing related to reading and (b) the FRD group showed the lowest phonological processing outcomes. Furthermore, CP correlated weakly with reading, but this relationship was fully mediated by rapid automatized naming. Conclusion: Although CP phonological skills are related to dyslexia, there was no strong evidence for a cascade from CP to phonology to reading. Deficits in CP at the behavioral level are not directly associated with dyslexia. [ABSTRACT FROM AUTHOR]