Purpose: We investigated whether impaired acoustic processing is a factor in developmental language disorders. The amplitude envelope of the speech signal is known to be important in language processing. We examined whether impaired perception of amplitude envelope rise time is related to impaired perception of lexical and phrasal stress in children with specific language impairment (SLI). Method: Twenty-two children aged between 8 and 12 years participated in this study. Twelve had SLI; 10 were typically developing controls. All children completed psychoacoustic tasks measuring rise time, intensity, frequency, and duration discrimination. They also completed 2 linguistic stress tasks measuring lexical and phrasal stress perception. Results: The SLI group scored significantly below the typically developing controls on both stress perception tasks. Performance on stress tasks correlated with individual differences in auditory sensitivity. Rise time and frequency thresholds accounted for the most unique variance. Digit Span also contributed to task success for the SLI group. Conclusions: The SLI group had difficulties with both acoustic and stress perception tasks. Our data suggest that poor sensitivity to amplitude rise time and sound frequency significantly contributes to the stress perception skills of children with SLI. Other cognitive factors such as phonological memory are also implicated.