Speech intelligibility in tone language (Chinese) laryngectomy speakers

Tone language speakers use lexical tone or fundamental frequency to signal meaning. Therefore, native tone language alaryngeal speakers encountering difficulty imparting lexical tone variation would suffer loss of speech intelligibility. This study examines the intelligibility of lexical tone produced by four different alaryngeal speech methods, namely: oesophageal speech, electrolarynx, a pneumatic device and tracheo-oesophageal speech. Isolated and embedded monosyllabic Chinese words produced by 53 alaryngeal speakers were presented to three normally hearing, young adult listeners with no prior exposure to laryngectomy speech. The listeners transcribed the speech orthographically. Significant differences were found in the intelligibility level between the different speech methods. Listeners' responses were also pooled together and analysed for tone and segmental errors. Errors of tone alone were found to occur more often than segmental errors.