The effect of clear speech on speech intelligibility associated with Cantonese alaryngeal speakers

Abstract

The current study aimed to investigate the effect of clear speech (CS) on speech intelligibility associated with alaryngeal speakers using electrolaryngeal speech (EL), esophageal speech (ES) and tracheoesophageal speech (TE). Voice recordings of 11 sentences randomly selected from the Cantonese Sentence Intelligibility Test (CSIT; Lo, 1999) were obtained from 9 EL speakers, 11 ES speakers and 12 TE speakers. Each alaryngeal speaker produced the sentences comprised of 5 to 15 words twice; once in habitual speech (HS) and once in CS. Two naïve listeners orthographically transcribed each sentence to calculate the CSIT intelligibility score and rated the intelligibility of each sentence using an 11-point equal appearing interval (EAI) scale. Results indicated no significant main effect on speaking condition as revealed by CSIT intelligibility scores and intelligibility ratings, while an increase in intelligibility was observed in both measures in all speaker groups. The highest increase (+9.092%) in the CSIT intelligibility score was observed in EL speakers, while ES speakers had the largest increase (+7.626%) in the intelligibility rating using the EAI scale. TE speakers had the lowest increase in both measures. Future research should investigate the effect of longer training protocols to improve the intelligibility of alaryngeal speakers using CS.