Electronic Theses and Dissertations




Y Jhang



Date of Award


Document Type


Degree Name

Doctor of Philosophy


Comm Sciences and Disorders


Speech Lang Sci & Disorders

Committee Chair

D. Kimbrough Oller

Committee Member

Eugene Buder

Committee Member

Yeh Hsueh

Committee Member

Dale Bowman


The dissertation contains two papers on the theme of flexibility in infant communication using an infrastructural approach. An infrastructural approach considers infant communication in terms of properties of human language (i.e., spontaneous vocalization, functional flexibility, social interactivity, and etc.). Infants' vocal flexibility is explored in two ways in the dissertation: 1) How infants use sounds with varying emotional valences, a primary determiner of their communicative functions, and when this infrastrucutral property emerges (the first paper, in Chapter 2), and 2) what role the voice plays independently and jointly with the face in the transmission of affect and vocal type (the second paper, in Chapter 3). The first paper demonstrates that infants explore vocalizations in protophones and associate them with a range of affect as early as the first month of life. That is, all the protophone types we examined showed strong functional flexibility by showing significantly more neutral facial affect than cry and significantly less negative facial affect than cry. Further, infant protophones were functionally flexible across all three months, being differentiated from cry at all the ages. The second study revealed an important distinction in the use of face and voice in affect vs. protophone expression. Affect was transmitted with audio and video being flexibly interwoven, suggesting infant vocal capabilities establish a foundation for the flexible use of the voice, as is required in language. Both works contribute to our understanding of the path leading to the infants' speech capacity.


Data is provided by the student.

Library Comment

dissertation or thesis originally submitted to the local University of Memphis Electronic Theses & dissertation (ETD) Repository.