The goals of this study were to (a) compare the vowel space produced by a person with congenital aglossia (PWCA) with a typical vowel space; (b) investigate listeners’ intelligibility for single vowels produced by the PWCA, with and without visual information; and (c) determine whether there is a correlation between scores of speech intelligibility of PWCA speech and the acoustic properties of those speech samples. The main objective of this study was to determine whether a PWCA was able to compensate for the lack of tongue and whether listeners were able to compensate perceptually for the possible atypical acoustics of the PWCA. Cineradiography for this article was limited to observation of gross function of the tongue base and mylohyoid. An audiovisual recording of the PWCA speaker’s output was obtained for a series of isolated vowels, diphthongized vowels, and vowels in monosyllables. Production of vowels was analyzed acoustically and perceptually. Vowels were presented to listeners under two conditions: audiovisual and audio only. Paired differences sample tests revealed no statistical differences in intelligibility for the audio versus audiovisual conditions. Mean intelligibility for vowels was 78.5% overall. Intelligibility was a function of vowel position, with the front vowels revealing the least intelligibility and the back vowels revealing the greatest intelligibility. Quantitative analysis of F1–F2 formant data revealed that the speaker’s front vowels showed greater distances from the back vowels when compared with the F1–F2 means of normative data.

This article is the second in a series that examines the intelligibility of a person with congenital aglossia (PWCA). Specific factors examined in this study included (a) intelligibility for meaningful words versus nonsense words, (b) intelligibility for consonant-vowel-consonant words (CVCs) as a function of phonemic segment types, and (c) whether there is a correlation between intelligibility for these factors and the acoustic properties of the speech samples. Results revealed greater intelligibility for meaningful versus nonsense CVCs, greater intelligibility for back, low, and high-back versus front vowels embedded in CVCs, and greater intelligibility for productions as a function of phonemic variables, which demonstrated the following hierarchy: initial consonant > consonant vowel > vowel consonant > final consonant. Further results suggest that consonant recognition was consistently affected by “vowel context.” This suggests that movement sequencing appeared to be of importance for speech perception in productions of a PWCA.

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This research examined cineradiographic films (CRF) of articulatory movements in a person with congenital aglossia (PWCA) during speech production of four phrases. Pearson correlations and a multiple regression model investigated co-variation of independent variables, positions of mandible and hyoid; and pseudo-tongue-dependent variables, positions of mylohyoid and tongue base. Results suggest that backing/fronting of the mandible assisted the mylohyoid/tongue base in making mid-antero-posterior constrictions. Co-linearity findings suggest the best predictor of tongue base movement was mandible for back sounds. Hyoid movement was highly correlated with mandibular movement horizontally, but hyoid acted independently vertically and possibly with greater phonemic specialty in the PWCA. Findings suggest hyoid was a strong determinant of vertically dependent variable movement in all phrases. The extent of hyoid activity was a unique finding and one that may begin to explain relative intelligibility in this PWCA. Observed changes in vocal tract length may have influenced F2 transitional/vowel midpoint values.

Conclusion:This study has demonstrated the perception of different tastes in a PWCA. This is the first known report of umami being identified as a unique taste in a PWCA. Variations in threshold taste concentrations compared to normal individuals indicate certain gustatory dysfunction.