The Distribution of Forty Sounds in an Acoustic Space
Ivan R. King · The Journal of the Acoustical Society of America · 1974
Mean decibel power spectra were calculated for a half-second sample of each of 40 continuant sounds: 19 vowels, 6 vocalics, 11 fricatives, and 4 sibilants. Eigenvector studies were made of the entire set and of various subsets of the sounds. In every case the first few eigenvectors account for nearly all of the total variance. Similarly, nearly all of the total variance in every case is along the directions of the lowest-order cepstral components. When the 40 sounds are plotted in their principal eigenplane, a clear separation shows between high vowels, low vowels, voiced consonants, and unvoiced consonants. Some of the subsets also show, in their own principal eigenplanes, a geometric arrangement that corresponds to phonetic classes; but some do not. The principal eigenplanes of the various subsets do not coincide; an effort is made to exhibit the geometrical relationship between pairs of such planes. Some of these diagrams show additional separation of sets of sounds. In general, eigenplane plots are instructive and suggest further directions for study. [This work was carried out at the Institute for Defense Analyses, Princeton, New Jersey.]