The primary purpose of this study was to demonstrate the efficacy of the blending portion of the Promoting Awareness of Sounds in Speech (PASS) program, a comprehensive and explicit phonological awareness intervention curriculum designed for preschool children with speech and language impairments. A secondary purpose was to examine the effects of stimulus characteristics on responsiveness to the phonological awareness intervention via post-hoc analysis. A single-subject design was used to examine treatment effects among children with varying levels of communicative abilities. The PASS blending module was implemented with 11 children with speech and/or language impairments, following the establishment of a stable pretreatment baseline on a series of phonological awareness probes. After instruction, the children demonstrated substantial improvement in their blending ability, which appeared to be attributable to the intervention rather than environmental or maturational factors. These findings suggest that PASS blending training was an effective approach to phonological awareness instruction for the preschoolers with disabilities in our sample. Additionally, word frequency and neighborhood density were found to influence performance on some phonological awareness tasks. Specifically, children correctly blended high-frequency words more than low-frequency words, but they correctly blended words from lower-density neighborhoods more than words from higher-density neighborhoods. Findings are discussed with respect to predictions of the lexical restructuring hypothesis.
