To investigate the prosodic feature of artificial voice in cases of laryngectomy, the sound pressures and variances of five Japanese vowels in esophageal speech and an artificial larynx were measured and compared with same during normal speech. We found that the average pressure of the five vowels uttered by light phonation was the largest in normal speech. The pressure was smaller in cases of an artificial larynx, and smallest in esophageal speech. When uttered by subjectively rated equal loudness, the pressure variances of the same vowel in the artificial larynx were as small as in normal speech, while the variances were large in esophageal speech. The average pressure difference among the five vowels in artificial larynx was similar to that of normal speech, and was in order of /a/, /o/, /e/, /u/, and /i/. In esophageal speech, however, almost no pressure difference was observed among the five vowels. These results show that from the standpoint of sound pressure, the artificial larynx is more favorable than esophageal speech.
