In the past 10 years, important new theoretical insights into the range and nature of WM deficits and relation between these limitations and the language difficulties in SLI have occurred. New, robust diagnostic assessment tools and computerized treatment methods designed to enhance children's WM functioning have also been developed. The assessment, diagnosis, and treatment of the language difficulties in SLI should consider the potential influence of WM.

Aim 1 of this study was to examine the developmental changes in typically developing English-speaking children's syntactically based sentence interpretation abilities and sensitivity to word order. Aim 2 was to determine the psychometric standing of the novel sentence interpretation task developed for this study, because we wish to use it later with children with specific language impairment. Children listened to semantically implausible sentences in which noun animacy and the natural affordance between the nouns were removed, thus controlling for event probability. Using this novel “whatdunit?” agent selection task, 256 children 7–11 years old listened to two structures with canonical word order and two with noncanonical word order. After each sentence, children selected as quickly as possible the picture of the noun they believed was “doing the action.” Children interpreted sentences with canonical word order with greater accuracy and speed than those with noncanonical word order. Older children (mean age = 10 years, 8 months) were more accurate and faster than younger children (mean age = 8 years, 1 month) across all sentence forms. Both older and younger children demonstrated similar error patterns across sentence type. The “whatdunit?” task also proved to have strong validity and reliability, making it suitable for studies with children with specific language impairment.

The present study evaluated a two-mechanism memory model of the online auditory comprehension of object relative (OR) sentences in 7–11-year-old typically developing children. Mechanisms of interest included working memory storage (WMS) and attention focus switching. We predicted that both mechanisms would be important for comprehension. Forty-four children completed a listening span task indexing WMS, an auditory attention focus switching task, and an agent selection task indexing spoken sentence comprehension. Regression analyses indicated that WMS and attention focus switching accuracy each accounted for significant and unique variance in the children’s OR comprehension after accounting for age. Results were interpreted to suggest that WMS is important for OR comprehension by supporting children’s ability to retain both noun phrase 1 and noun phrase 2 prior to their reactivating noun phrase 1 from memory in order to integrate it into a developing structure. Attention focus switching was interpreted to be critical in supporting children’s noun phrase 1 reactivation, as they needed to switch their focus of attention momentarily away from ongoing language processing to memory retrieval.