ASA 129th Meeting - Washington, DC - 1995 May 30 .. Jun 06
5aSC5. Three acoustically predictable factors underlying vowel tongue
shapes.
David A. Nix
George J. Papcun
Los Alamos Natl. Lab., CIC-3, MS B265, Los Alamos, NM 87545
To obtain a low-dimensional, speaker-independent parameterization of vowel
tongue shapes, the three-mode factor analysis procedure PARAFAC [Harshman et
al., 693--707 (1977)] was applied to x-ray microbeam tongue
measurements of ten English vowels spoken by two male and two female subjects
in seven different /CVC/ contexts. PARAFAC reliably extracts three
speaker-independent, nonorthogonal factors. The resulting speaker-independent
factor coefficients cluster by vowel in three-dimensional articulatory space.
In two-dimensional projections, they qualitatively reflect the traditional
vowel quality chart. A multi-layer perception (neural network) independently
corroborates this solution: these tongue shape coefficients are significantly
more predictable from the corresponding acoustics than coefficients from either
the nonorthogonal two-factor solution or the orthogonally constrained
three-factor solution. These three factors also correspond qualitatively to the
three nonorthogonal factors extracted from Icelandic x-ray film vowel data
[Jackson, 124--143 (1988)]. Thus the current English solution
contradicts Jackson's distinction (based on Harshman et al.'s two-factor
English vowel solution) between language-independent and language-specific
vowel articulation primes. This low-dimensional, potentially cross-linguistic
representation could benefit speech recognition, coding, or synthesis
applications in which an acoustically correlated vowel tongue shape
parameterization is required.