Effect of total laryngectomy on vowel production: An acoustic study of vowels produced by alaryngeal speakers of Cantonese

Abstract

Purpose: To investigate the effect of total laryngectomy on vowel production, the present study examined the change in vowel articulation associated with different types of alaryngeal speech in comparison with laryngeal speech using novel derived formant metrics.

Method: Six metrics derived from the first two formants (F1 and F2) including the First and Second Formant Range Ratios (F1RR and F2RR), triangular and pentagonal Vowel Space Area (tVSA and pVSA), Formant Centralisation Ratio (FCR) and Average Vowel Spacing (AVS) were measured from vowels (/i, y, ɛ, a, ɔ, œ, u/) produced by oesophageal (ES), tracheoesophageal (TE), electrolaryngeal (EL), pneumatic artificial laryngeal (PA) speakers, as well as laryngeal speakers.

Result: Data revealed a general reduction in articulatory range and a tendency of vowel centralisation in Cantonese alaryngeal speakers. Significant articulatory difference was found for PA and EL compared with ES, TE, and laryngeal speakers.

Conclusion: The discrepant results among alaryngeal speakers may be related to the difference in new sound source (external vs internal). Sensitivity and correlation analyses confirmed the use of the matrix of derived formant metrics provided a more comprehensive profile of the articulatory pattern in the alaryngeal population.

Keywords:

• Cantonese alaryngeal speech
• formant range ratios
• vowel space area
• formant centralisation ratio
• average vowel spacing