Effect of vowel type on reliability of nasality ratings

Abstract

This study investigated the effects of high front (HF) vowels and low back (LB) vowels on inter-listener and intra-listener reliability in rating hypernasality. Audio recorded samples of two sentences, one containing only high front vowels and one containing only low back vowels, were judged by two expert listeners. Speakers were 25 children; 20 hypernasal and 5 with normal resonance. The inter-listener ratings for LB samples were more similar than the inter-listener ratings for HF samples ( t = 3.20, (24), p = .004). The mean difference between the two listeners’ ratings for the LB samples was 46.32 (S.D. 49.66) and for the HF samples 85.39 (S.D. 85.81). For intra-listener reliability, the ratings for the LB vowels were significantly more similar for one listener but not for the other. Additionally, the HF samples were rated as significantly more nasal than the LB samples. These findings suggest that listener reliability can be influenced by the vowel content of the stimulus. Learning outcomes: As a result of this activity, the participant will be able to (1) describe the general effects of phonemes on judgments of hypernasality; (2) describe the specific effects of vowel types on the reliability of inter-listener and intra-listener judgments of nasality; and (3) appreciate how this information might be used in clinical and research applications.