Date of Defense

Summer 5-17-2012

Date of Graduation

Spring 4-28-2012


Speech Pathology and Audiology

First Advisor

James M. Hillenbrand, Speech Pathology and Audiology

Second Advisor

Stephen Tasko, Speech Pathology and Audiology

Third Advisor

Helen Sharp, Speech Pathology and Audiology


Several studies have examined the perception of sinewave speech. Early work showed that listeners could transcribe sinewave sentences. Recent work on sinewave vowels found that listeners could recognize sinewave speech at the phonetic level with moderate (about 50-55%) accuracy. Sinewave vowel intelligibility scores improve significantly when preceded by a sinewave carrier phrase, an effect that disappears when the carrier phrase is removed. The present study was designed to examine this carrier phrase enhancement effect and analyze whether listeners require the carrier phrase to be intelligible to produce increased intelligibility scores. Sinusoidal carrier phrases and /hVd/ syllables were generated from recordings of an adult male and presented to listeners. Carrier phrases were recorded in both English and Japanese – a language unfamiliar to the 43 participants who served as listeners. All participants were students who had completed an introductory phonetics course. The conditions containing the Japanese carrier phrases resulted in intelligibility rates between 48 and 50%, roughly the same as the sinewave syllables being presented in isolation. The condition resulting in the highest intelligibility rate, 77%, included a single English carrier phrase, “The next word on the list is…” repeated on each of the 240 trials. The results indicate that the carrier phrase enhancement effect occurs only in the presence of an intelligible carrier phrase to signal to the listener to process the utterance as speech.

Access Setting

Honors Thesis-Open Access

4.13 PPT.pptx (1049 kB)