Analysis of the three-dimensional tongue shape using a three-index factor analysis model

Abstract

Three-dimensional tongue shape during vowel production is analyzed using the three-mode PARAFAC (parallel factors) model. Three-dimensional MRI images of five speakers (9 vowels) are analyzed. Sixty-five virtual fleshpoints (13 segments along the rostral-caudal dimension and 5 segments along the right-left direction) are chosen based on the interpolated tongue shape images. Methods used to adjust the alignment of MRI images, to set up the fleshpoints, and to measure the position of the fleshpoints are presented. PARAFAC analysis of this 3D coordinate data results in a stable two-factor solution that explains about 70% of the variance.

Structure, Movement, Sound, and Perception

“…They are configured such that one pattern produces a continuum from /i/-like to /a/-like vocal tract shapes while another represents an /æ/-like to /u/-like continuum, suggesting that they represent a coordination of the speech articulators necessary for vowel production. The results are similar to factor analyses of tongue shape (Harshman, Ladefoged, and Goldstein, 1977; Shirai and Honda, 1977; Nix, Papcun, Hogden, and Zlokarnik, 1996; Zheng, Hasegawa-Johnson, and Pizza, 2003), shaping components used in other articulatory models (Berry, 2003; Maeda, 1990, 1991), as well as analogous research on vocal tract area functions (Mokhtari et al, 2007). Some recent work has also shown that the shape of these patterns can be derived theoretically from calculations of acoustic sensitivity functions of the nonuniform neutral area functions of speakers (Story, 2007).…”

Synergistic modes of vocal tract articulation for American English vowels

“…A reanalysis of these data by Nix et al ͑1996͒, however, showed that two factors could, in fact, describe the Icelandic tongue shapes too. More recently, Zheng et al ͑2003͒ have applied a factor analysis to tongue shapes determined from 3-D image sets based on MRI. While their results were not identical to previous studies, they suggest that a large percentage of the variance in tongue shape for vowels can be described with two shaping factors.…”

Time dependence of vocal tract modes during production of vowels and vowel sequences

“…At nearly the same time Shirai and Honda (1977) demonstrated that the tongue configuration could be described by two empirically-determined displacement patterns. Subsequent studies of tongue shape using either factor or principal component analyses have similarly concluded that two shaping patterns can generally describe the midsagittal tongue shape during vowel production in various languages (Johnson et al 1993;Nix et al 1996;Hoole, 1999;Zheng et al 2003;Iskarous, 2005). In each study, the shaping patterns more or less conform to the view that one pattern captures the forward and upward movement of the tongue, while a second pattern describes upward and backward motion.…”