The use of Lombard effect in improving loudness problem among alaryngeal speech of Cantonese

Abstract

Lombard effect is an involuntary increase of vocal intensity in response to background noise. This study investigated the use of Lombard effect to overcome the loudness problem of alaryngeal speech and explored its effect on speech intelligibility, with laryngeal speech as comparison. Fifty-two Cantonese-speaking laryngeal and alaryngeal speakers were recruited for the study: 10 normal laryngeal (NL), 10 tracheoesophageal (TE), 11 esophageal (SE), 8 pneumatic artificial (PA) and 13 electrolaryngeal (EL) speakers. Reading tasks involving three 10-syllable Cantonese sentences under ten background conditions: quiet, 60 dB, 65 dB, 70 dB, 75 dB, 80 dB, 85 dB, 90 dB, 95 dB and 100 dB white background noise were implemented. Significant increase in output intensity was shown in all speaker type at all nine noisy conditions. Five naïve Cantonese speakers rated the speech intelligibility of all recorded samples. Speech intelligibility of laryngeal speakers was significantly higher than that of alaryngeal speakers at all conditions. No significant improvement or reduction of intelligibility across conditions was revealed for all speaker types. Further studies investigating the Lombard effect on speech intelligibility of alaryngeal speakers was suggested with task modification. Clinical implication for applying Lombard effect in speech rehabilitation for laryngectomee was discussed.

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