Some organization principles in early speech development

In early speech development, progressive gains in phonetic ability represent progress in multiple domains (e.g., sensory, perceptual, cognitive, linguistic, and neuromotor) all of which are ultimately conveyed through the speech motor system. Accordingly, the comprehensive understanding of speech development requires knowledge about age-related changes in speech motor performance and about the factors affecting those changes during the various phases of speech development. In this chapter, we consider why motor-based descriptions are essential for addressing long-standing practical and theoretical issues regarding early speech development. We also present a conceptual framework for studying early speech motor development, which guides our current line of research inquiry. The conceptual framework proposes that developmental stages in speech motor behavior are guided by production constraints and catalysts to speech motor performance: Production constraints are factors that limit speech production abilities in young children and catalysts are factors that engender change toward mature speech. Finally, we consider findings from our studies on early speech motor development that are motivated by the framework. 10.