Purpose: Early language and speech acquisition can be delayed in twin children, a twinning effect that diminishes between 4 and 6 years of age in a population-based sample. The purposes of this study were to examine how twinning effects influence the identification of children with language impairments at 4 and 6 years of age, comparing children…

Purpose: This review article summarizes a program of longitudinal investigation of twins' language acquisition with a focus on causal pathways for specific language impairment (SLI) and nonspecific language impairment in children at 4 and 6 years with known history at 2 years. Method: The context of the overview is established by legacy scientific…

Purpose: This study investigates the heritability of language, speech, and nonverbal cognitive development of twins at 4 and 6 years of age. Possible confounding effects of twinning and zygosity, evident at 2 years, were investigated among other possible predictors of outcomes. Method: The population-based twin sample included 627 twin pairs and 1…

Purpose: This study investigated the etiology of late language emergence (LLE) in 24-month-old twins, considering possible twinning, zygosity, gender, and heritability effects for vocabulary and grammar phenotypes. Method: A population-based sample of 473 twin pairs participated. Multilevel modeling estimated means and variances of vocabulary and…

The effect of neighborhood density on optional infinitives was evaluated for typically developing (TD) children and children with Specific Language Impairment (SLI). Forty children, twenty in each group, completed two production tasks that assessed third person singular production. Half of the sentences in each task presented a dense verb, and…

Purpose: The mean length of children's utterances is a valuable estimate of their early language acquisition. The available normative data lack documentation of language and nonverbal intelligence levels of the samples. This study reports age-referenced mean length of utterance (MLU) data from children with specific language impairment (SLI) and…

Purpose: The aim of this study was to investigate the language outcomes of 7-year-old children with and without a history of late language emergence at 24 months. Method: One hundred twenty-eight children with a history of late language emergence (LLE) at 24 months and 109 children with a history of normal language emergence (NLE) at 24 months…

This study reports on a comparison of the use and knowledge of tense-marking morphemes in English by first language (L1), second language (L2), and specific language impairment (SLI) children. The objective of our research was to ascertain whether the L2 children's tense acquisition patterns were similar or dissimilar to those of the L1 and SLI…

Purpose: Although mean length of utterance (MLU) is a useful benchmark in studies of children with specific language impairment (SLI), some empirical and interpretive issues are unresolved. The authors report on 2 studies examining, respectively, the concurrent validity and temporal stability of MLU equivalency between children with SLI and…

A review of research on how cognition relates to language in children with language impairments discusses terminology and analyzes the basic mapping problem. Evidence for a variety of hypotheses related to the issue are examined. (CL)

A plural elicitation task and a nominal compounding task were administered to 18 children (age 5-6 years) with specific language impairment (SLI) and 2 control groups. SLI children's performance was affected by input frequency; three explanations within a model of linguistic normalcy are proposed to account for this frequency effect. (Author/DB)

Two studies investigated the syntactic bootstrapping abilities of 5- and 7-year-old children with specific language impairment and comparison groups matched for equivalent language level or chronological age. Only typically developing 5-year-olds showed evidence of using syntactic clues. However, continued syntactic growth was seen in all…

This study explored the acquisition of regular and irregular past tense in 21 children with specific language impairment. The findings support a morphosyntactic rather than morphophonological learning model, such as the extended optional infinitive model, with regard to the limitations in finiteness marking and for affected children. (Contains…

This longitudinal study evaluated grammatical judgments of "well formedness" of children (N=21) with specific language impairment (SLI). Comparison with two control groups found that children with SLI rejected morphosyntactic errors they didn't commit but accepted errors they were likely to make. Findings support the extended optional infinitive…

Fifty-seven children (ages 5-8) with and without specific language impairment (SLI) participated in judgment and elicitation tasks designed to evaluate their understanding of irregular verb forms. Differences between SLI and control children were observed in their productions and relative levels of sensitivity to infinitive errors in finite…