Case study: Optimality theory and the assessment and treatment of phonological disorders

Recently, the development of the constraint-basedframework of optimality th eory has been adopted and applied to the assessment and treatment of childr en with phonological disorders. This paper provides a demonstration of the application of optimality theory to assessment and treatment of a single ch ild with a phonological disorder. First, a tutorial of the theory is provid ed. Then, several prototypical error patterns evident in the child's produc tions are analyzed within the framework. These errors are accounted for by assuming that constraints against marked structure are ranked over constrai nts that require faithfulness to input,ms within the child's grammar. Follo wing that, a demonstrating of how optimality theory accounts for different types of variation in the child's productions is provided. These different types of variation are revealing the-true nature of certain error patterns, particularly an apparent pattern of cluster reduction. Finally, the result s of the analysis lead to suggestions for treatment that focus on the demot ion of markedness constraints below faithfulness constraints.