The effects of articulation errors on perceived nasality in speakers with repaired cleft lip and/or palate

Articulation errors and hypernasality, or nasal sounding speech, are common deficits seen in children with repaired cleft lip and/or palate. These two deficits affect intelligibility, but may also have an effect on each other. This study was designed to investigate how severity of articulation errors affects individual’s perceived nasality and the influence of training on the ability to separate the two when listening to speech. Eight stimuli with varying degrees of articulation errors and nasality were chosen by expert listeners for the study. During the study, undergraduate and graduate students rated the stimuli for perceptual nasality. The degree of articulation errors was found to affect the amount of nasality listeners perceived. Listeners attended to articulation errors when nasality was mild, to both when nasality was moderate, and to nasality when the nasality was severe. Further, undergraduates’ nasality ratings were more affected by articulation; however, graduate students’ ratings were more variable. These findings support the importance of articulation therapy for children with repaired cleft palates to both decrease articulation errors and decrease perceived nasality. Further, this study highlights the need for including awareness of this interaction in the training of speech-language pathologists in order for the “gold standard” of perceptual judgements to remain a valid and reliable measure.