Verbal working memory (VWM) deficits are common in individuals with developmental language disorder (DLD) but are not well understood. This study evaluated how both memory and language production factors influence VWM performance in children and adults with DLD, focusing on the influence of serial position, phonological activation (PA), and lexical frequency. Participants were 30 children with DLD and 26 with typical language (TL), and 21 adults with DLD and 23 with TL. The participants completed a listening span task in which they were asked to recall the final words of sentences in sets of increasing size. Responses (dependent variable) were coded as correct, incorrect, or no response. Final words were coded for frequency, serial position within the set, and PA (number of occurrences of the initial phoneme, vowel, and whole word in the task). These variables, along with age and language status, were entered as predictors in mixed-effects multinomial regression models. Extreme serial position, greater PA, and higher frequency reduced incorrect and no responses. These effects were attenuated for the DLD group, and the effect of greater PA varied with set size. The findings suggest that for individuals with DLD, VWM performance is affected by more limited effective language experience and by the dynamic task demands.
Keywords: developmental language disorder; listening span; verbal working memory.