Verbal mediation of cognition in children with specific language impairment.

Private speech (PS) and inner speech (IS) are thought to be functionally important for children's and adults' cognition, but they have not been studied systematically in children with specific language impairment (SLI). Participants were 21 children with SLI (7-11 years, expressive or receptive verbal IQ ≤ 75, nonverbal IQ ≥ 84) and 21 age- and nonverbal IQ-matched controls. Participants completed three sets of Tower of London problems: one with no dual task (PS condition), one with articulatory suppression, and one while foot tapping (control condition). Participants also completed a digit span task. There was no group difference in the susceptibility of Tower of London performance to articulatory suppression, but the PS of the SLI group was less internalized than that of the controls on both tasks. The findings suggest that children with SLI experience a significant delay in the development of PS/IS, but that their PS/IS is effective for Tower of London performance in middle childhood. Findings are discussed with reference to the interpretation of the nonlinguistic deficits associated with SLI, and in terms of clinical implications.

The roles of private speech and inner speech in planning during middle childhood: evidence from a dual task paradigm.

Children often talk themselves through their activities, producing private speech that is internalized to form inner speech. This study assessed the effect of articulatory suppression (which suppresses private and inner speech) on Tower of London performance in 7- to 10-year-olds, relative to performance in a control condition with a nonverbal secondary task. Experiment 1 showed no effect of articulatory suppression on performance with the standard Tower of London procedure; we interpret this in terms of a lack of planning in our sample. Experiment 2 used a modified procedure in which participants were forced to plan ahead. Performance in the articulatory suppression condition was lower than that in the control condition, consistent with a role for self-directed (private and inner) speech in planning. On problems of intermediate difficulty, participants producing more private speech in the control condition showed greater susceptibility to interference from articulatory suppression than their peers, suggesting that articulatory suppression interfered with performance by blocking self-directed (private and inner) speech.

Brief report: Inner speech impairment in children with autism is associated with greater nonverbal than verbal skills.

We present a new analysis of Whitehouse, Maybery, and Durkin's (2006, Experiment 3) data on inner speech in children with autism (CWA). Because inner speech development is thought to depend on linguistically mediated social interaction, we hypothesized that children with both autism and a nonverbal > verbal (NV > V) skills profile would show the greatest inner speech impairment. CWA and typically developing controls (n = 23 in each group) undertook a timed mathematical task-switching test, known to benefit from inner speech use. Participants completed the task with and without articulatory suppression (AS), which disrupts inner speech. The hypothesis was supported: AS interference varied with cognitive profile among CWA but not among controls. Only the NV > V autism group showed no AS interference, indicating an inner speech impairment.