Correspondence between vocal intensity and listeners' estimation of perceived nasality in cleft palate speech

Abstract EN

A relationship often superseded in the management of individuals with cleft lip and/or palate is the association between phonatory features and deviant resonance.

This study was, aimed (1) to explore a relationship between loudness of voice (phonatory feature) and nasality (defiant resonance) and (2) to quantify the correlation between intensity and perceived nasality in the utterances of individuals with repaired cleft lip and palate.

The experiment was conducted in two stages.

The first stage involved eight subjects with repaired cleft lip and palate producing sustained vowels /a/, l\l and /u/ in isolation and two sentences comprising three meaningful bisyllabic words in Tamil.

Sentence 1 was loaded with non-nasal sounds and sentence 2 with nasal consonants.

The subjects produced these at four different loudness levels viz.

loud, normal, soft, and whisper.

Stage 2 involved fifteen listeners (undergraduate students in Speech and Hearing), who were required to rate the degree of perceived nasality of the speech samples obtained at the different loudness level in Stage 1.

They were provided with a 5-point equal appearing interval-rating scale ranging from hyponasality to severe hypernasality.

Results indicated maximum nasality was perceived while the subjects produced voices of loud intensity.

This is discussed with reference to findings from the literature and its practical implications.