The role of supralexical prosodic units in speech production: Evidence from the distribution of speech errors

The current dissertation represents one of the first systematic studies of the distribution of speech errors within supralexical prosodic units. Four experiments were conducted to gain insight into the specific role of these units in speech planning and production. The first experiment focused on errors in adult English. These were found to be systematically distributed within the highest-level supralexical prosodic unit, the Intonational Phrase (IP), providing evidence for its psychological reality. The specific distribution of errors---fewest in unit-initial position, with a gradual increase in errors across the unit---was interpreted to suggest that the IP functions as a planning domain: the unit is activated as a whole, and activation gradually decays with time leading to an increase in errors. The second experiment was motivated by the idea that a decrease in IP activation is best understood in the context of working memory processes. Children's speech was examined in preference to adult speech because it is less automatized and so likely more influenced by working memory. The findings were that children with better working memories produced shorter IPs and relatively more anticipatory errors than children with poorer working memories. The results provided further evidence for the role of IPs in planning. The third and fourth experiments extended the investigation to another language, Korean, and examined the role of a mid-level prosodic unit, the Accentual Phrase (AP), in planning and production. The results indicated the same pattern of error distribution in the Korean IP as in the English IP. In contrast, more errors occurred in AP-initial position than in the second half of the unit, and the elicited errors tended to preserve AP-internal structure. The results were interpreted to suggest that the AP provides a structural frame within which elements are slotted for production. Overall, the results are consistent with the idea that these units play a critical role in the planning and production process. The results also suggest that different units within the prosodic hierarchy function differently: the IP functions as a planning domain, and mid-level units (i.e., AP) provide the structure needed to accomplish serial ordering in speech.;This dissertation includes previously published co-authored material.