The long-term goals are to understand how preschool children with functional (nonorganic) phonological delays acquire the sound system of language, and to identify the factors that accelerate phonological learning in clinical treatment. The specific aim of the proposed research is to extend models of spoken word recognition to the study of phonological learning in testing the hypothesis that the structure of words differentially affects children's acquisition of speech sounds. Project 1 evaluates the acquisition of novel (non)words as an apparent jumpstart to phonological learning. Project 2 assesses the effects of long-term priming as a potential learning mechanism that accelerates phonological learning. The planned studies utilize experimental single-subject design to induce phonological generalization in treatment, with the translational mission of improved efficacy of clinical practice. The theoretical contributions are to psycholinguistic and developmental theories in elaborating the effects of the statistical regularities of language on the acquisition process as realized in a population of children with atypical linguistic development. PUBLIC HEALTH RELEVANCE::The proposed research focuses on the success of clinical treatment for preschool children who have been diagnosed with speech sound delays with no known origin. The goal is to identify the treatment variables that will help children to learn and correctly produce speech sounds. Two treatment factors will be tested: (1) the kinds of words that are taught and (2) the methods of word presentation.