No abstract

Five laryngectomized, tracheoesophageal (TE) speakers completed a series of phonatory tasks developed to assess (a) aerodynamic and acoustic properties of TE voice and (b) aerodynamic and myoelastic contributions to the mediation of fundamental frequency change. These TE speakers' voices were characterized by increased trans-source airflow rates, comparable source driving pressures, and decreased airway resistances in comparison with standard esophageal speakers. TE speakers were capable of adjusting their voicing sources on a myoelastic basis to influence F o change. This result, coupled with findings that confirm aerodynamic contributions to TE phonation, are intepreted to suggest that TE voice production should be regarded as an aerodynamic-myeolastic event. Findings are integrated with existing data to highlight fundamental differences among TE, esophageal, and normal voice production.

To provide information about the ultimate acceptability of various types of alaryngeal speech, 37 listeners rated nine speakers with normal phonation in relation to two groups of superior alaryngeal speakers: five who used esophageal speech and four who used artificial larynges. Normal speech was rated significantly more acceptable than any form of alaryngeal speech studied. Speech produced with a Tokyo artificial larynx was rated significantly more acceptable than all other types of alaryngeal speech. Superior esophageal speech was significantly preferred over Western Electric reed and Bell electrolarynx speech. Listeners also categorized each of the 18 speakers as a normal speaker or not a normal speaker. The nine alaryngeal speakers were all classified as nonnormal, while eight of the nine normal subjects were classified as normal.

The perception and production of linguistic tone was investigated in utterances spoken by Thai alaryngeal speakers. Thai is a tone language with five phonemic tones. High-quality tape recordings of five monosyllabic words produced by 2 esophageal, 1 electrolaryngeal, and 5 normal, native Thai speakers were subjected to perceptual and acoustic analysis. Results from the phonemic identification tests indicated that tones produced by alaryngeal speakers were not only perceived at much lower levels of accuracy than those produced by normal speakers, but the patterns of tonal confusions for alaryngeal speakers were also dissimilar to those for normal speakers. Results from fundamental frequency (Fo) analysis revealed that the performance deficit of alaryngeal speakers could be related to specific characteristics of their Fo contours. Findings are interpreted to highlight the importance of (a) language, (b) type of prosody, (c) form of alaryngeal speech, and (d) Fo level and direction on linguistic assessments of Fo control in alaryngeal speech.

Qi [J. Acoust. Soc. Am. 88, 1228-1235 (1990)] has demonstrated that (1) linear predictive (LP) methods can be used to separate vocal tract transfer functions from source functions of vowels produced by alaryngeal talkers and that (2) vowels synthesized with reconstructed transfer functions and totally synthetic voicing excitation sources have improved source-related properties over those present in the original vowels. Here, an extension of this work which is directed to the general goal of developing systems (devices) to enhance the quality of alaryngeal speech is reported. The specific goal of the present project was to determine whether speech, i.e., words spoken by female esophageal and tracheoesophageal talkers, could be enhanced by means of LP-based analysis and synthesis methods. Words spoken by four female alaryngeal talkers were analyzed and synthesized. A perceptual evaluation was completed to permit the quality of the synthetic and the original words to be compared. Listeners generally preferred to listen to the synthesized words, indicating that alaryngeal speech enhancement was accomplished.