Keywords

Vowels, Centralization ration, acoustic measures

Abstract

Acoustic measures calculated from the formant frequencies of corner vowels, such as the vowel space areas of triangles or quadrilaterals, have often been used as a window into articulatory function. Other measures, such as the formant centralization ratio (Sapir, Ramig, Spielman, & Fox, 2010), have been suggested as more sensitive alternatives. The purpose of this study was to compare changes in acoustic and kinematic measures of articulation across soft, comfortable, and loud speech conditions using both corner vowel-based and sentence level metrics. There were 19 participants, 9 male and 10 female, with ages ranging from 20 to 34 years. Each participant had electromagnetic sensors attached to their tongue, jaw, and lips. It was anticipated that the acoustic measures would parallel the changes observed in the kinematic measures as articulation changed across intensity levels. Vowel space area (VSA) and vowel articulation index (VAI) were computed from the three corner vowels, /A, i, u/. Articulatory-acoustic vowel space (AAVS), a sentence-level acoustic measure (Whitfield & Goberman, 2014), was computed from the continuous formant histories of all voiced segments in a sentence. Kinematic vowel space area (KVSA), kinematic vowel articulation index (KVAI), and articulatory kinematic vowel space (AKVS) were the kinematic equivalents of the acoustic measures, and were newly developed for the present study. Stroke metrics based on the speed history of the lingual movements were also used to reveal average kinematic features of the articulatory gestures in each participants speech. The data revealed that the isolated acoustic and kinematic measures that were based on the segmented corner vowels (VSA, VAI, KVSA, KVAI) did not change significantly across the three intensities. The sentence-level continuous measures of articulatory working space (AAVS and AKVS) increased with speech intensity. The sentence-level kinematic metrics based on the lingual speed history also changed significantly with intensity, including increased onset speed, peak speed, mean speed, and distance of the articulatory strokes. Stroke duration decreased as speech intensity increased, while hull area increased. These findings suggest that both acoustic and kinematic measures based on segmented corner vowels are not as sensitive to loudness-related changes in articulation as the more continuous sentence-level measures. Metrics that include the dynamic contributions of both consonant and vowel articulation may capture relevant changes that are not detected by measures based on vowel midpoints.

Original Publication Citation

Dromey, C., Palmer, P. & Whitfield, J. (2017). Effects of speech intensity on acoustic and kinematic articulatory working space. Poster presented at the 7th International Conference on Speech Motor Control, Groningen, Netherlands.

Document Type

Poster

Publication Date

2017

Language

English

College

David O. McKay School of Education

Department

Communication Disorders

University Standing at Time of Publication

Full Professor

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