This study examined the effects of overt phonologic impairment (disordered speech) on phonological awareness, verbal working memory, and letter knowledge. Forty-five children--29 with moderate to severe productive phonologic impairment at the inception of the project and 16 without impairment--were followed from mean age 3-6 to age 6-0. Fifteen participants with impairment were matched on gender and mental age to 15 without impairment for certain aspects of the analysis. The children with phonologic impairment performed significantly worse than their controls on tasks of verbal working memory, phoneme segmentation, and letter identification. In addition, a path analysis revealed working memory to be a potentially important mediating variable. The investigators also measured productive syntax, which, although associated with productive phonology and working memory, was not associated with letter identification.
