Unifying Speech and Language in a Developmentally Sensitive Model of Production.

Speaking is an intentional activity. It is also a complex motor skill; one that exhibits protracted development and the fully automatic character of an overlearned behavior. Together these observations suggest an analogy with skilled behavior in the non-language domain. This analogy is used here to argue for a model of production that is grounded in the activity of speaking and structured during language acquisition. The focus is on the plan that controls the execution of fluent speech; specifically, on the units that are activated during the production of an intonational phrase. These units are schemas: temporally structured sequences of remembered actions and their sensory outcomes. Schemas are activated and inhibited via associated goals, which are linked to specific meanings. Schemas may fuse together over developmental time with repeated use to form larger units, thereby affecting the relative timing of sequential action in participating schemas. In this way, the hierarchical structure of the speech plan and ensuing rhythm patterns of speech are a product of development. Individual schemas may also become differentiated during development, but only if subsequences are associated with meaning. The necessary association of action and meaning gives rise to assumptions about the primacy of certain linguistic forms in the production process. Overall, schema representations connect usage-based theories of language to the action of speaking.