An acoustic study of vowels produced by Cantonese alaryngeal speakers using clear speech

Abstract

Alaryngeal speech is an alternative method of verbal communication following the removal of the larynx. Common alaryngeal speaking methods include esophageal (ES) speech, tracheoesophageal (TE) speech, and speech produced using an electrolarynx (EL). A recent study [Hui et al., in press, Folia Phoniatr Logop] demonstrated better intelligibility in Cantonese alaryngeal speakers while using clear speech (CS) compared to their everyday ‘habitual speech’ (HS). Yet the correlated change in the acoustics associated with CS is still not clear. The purpose of this study was to assess the acoustic characteristics of vowels produced by Cantonese alaryngeal speakers during HS and CS conditions. Thirty-one alaryngeal speakers (9 EL users, 10 ES speakers, and 12 TE speakers) produced sentences from the Cantonese Sentence Intelligibility Test in HS and CS. Acoustic analyses considered formants (measured by reassigned spectrogram), vowel space area (VSA) and vowel duration across alaryngeal speaking methods and styles. We also examined these acoustic differences in relation to duration of alaryngeal speech use and intelligibility. Results suggest that EL users had larger VSAs and larger increases in vowel duration while using CS compared to ES and TE speakers. Future research will examine the effects of refined CS protocols on improving acoustic and perceptual characteristics of Cantonese alaryngeal speech.