Acoustic characteristics of speech produced with an electronic artificial larynx

Abstract

This study investigated the acoustic characteristics of speech produced with an electronic artificial larynx (electrolarynx). Five normal-speaking adult males were taught to use an electrolarynx, and each talker recorded a set of speech materials in his normal voice and with an electrolarynx. The recordings were subjected to analyses which included: (1) intensity level measurements of speech as well as the direct radiated sound from the electrolarynx; (2) speech-duration measurements; (3) spectral analysis of the radiated masking sound from the electrolarynx; and (4) formant frequency estimates derived from the spectrum of a linear prediction inverse filter. Results indicated that the overall intensity of electrolarynx speech was similar for the five talkers, but that intensity of the radiated noise, and hence speech-to-noise ratios, varied considerably among talkers. In addition, talkers required about 50% more time to produce speech with an electrolarynx, indicating modification of articulatory behavior. Spectral composition of the radiated sound from the electrolarynx varied from talker-to-talker. Formant frequencies for a given talker were similar for the normal voice and the electrolarynx productions, but the intensity relationships between formants was different in the two modes of production. [Research supported by NINCDS and a grant from the Samuel W. Traylor Foundation.]