Date of Award


Degree Name

Master of Arts


Speech, Language and Hearing Sciences


Speech Pathology and Audiology

First Advisor

Dr. Stephen Tasko

Second Advisor

Dr. James Hillenbrand

Third Advisor

Dr. Michael Clark

Access Setting

Masters Thesis-Open Access


This study characterized the speech motor transformations that underlie speech clarity changes in a group of 49 healthy young speakers. Clarity judgments based on auditory perception of the speech samples were determined by a panel of 30 undergraduate and graduate students. This study specifically aimed to characterize (1) the auditory-perceptual judgments of clarity, (2) the acoustic measures of clear and causal speech, (3) the temporal and spatial features of articulatory movements of clear and casual speech, and (4) test the hypothesis that auditory perceptual scaling of clarity (perceptual salience) would be associated with kinematic indicators of physical effort.

Results suggested clear speech is accompanied by changes in both the spatial and temporal features of speech motor output. However, temporal measures were more strongly correlated with perceptual ratings of clarity. Auditory perceptual scaling of clarity was not found to be associated with physical effort as defined by a change in peak speed.