Case Study: Optimality Theory and the Assessment and Treatment of Phonological Disorders

Recently, the development of the constraint-based framework of optimality theory has been adopted and applied to the assessment and treatment of children with phonological disorders. This paper provides a demonstration of the application of optimality theory to the assessment and treatment of a single child with a phonological disorder. First, a tutorial of the theory is provided. Then, several prototypical error patterns evident in the child's productions are analyzed within the framework. These errors are accounted for by assuming that constraints against marked structure are ranked over constraints that require faithfulness to input forms within the child's grammar. Following that, a demonstration of how optimality theory accounts for different types of variation in the child's productions is provided. These different types of variation are revealing of the true nature of certain error patterns, particularly an apparent pattern of cluster reduction. Finally, the results of the analysis lead to suggestions for treatment that focus on the demotion of markedness constraints below faithfulness constraints.