Determinación del locus de las oclusivas sordas mediante ecuaciones polinómicas: primera aproximación

Abstract

In 1955, an article by Delattre, Lieberman y Cooper proposed the existence of an acoustical point that would allow the categorization of the articulation point from the next vowel of a VCV sequence. This point was called "locus". Subsequent studies carried out by Lehiste and Peterson (1961), Fant (1973), and Kewley.Port (1982)etc. in order to confirm the reality of such a parameter, concluded that it was not possible to establish such an invariant point. We have found that the locus is an intersection line, formed by the F2 values of the neighboring vowels of a VCV sequence. F2 values are approximated by means of a three-degree and two-degree polynomial (y = ax³ + bx² + ex + d and y = ax² + bx + e), relating time and frequency. 609 data samples from 10 speakers (6 male and 4 female) that produced VCV tokens in all vowel contexts in Spanish were analized. Three intervals were established for each articulation point. Bilabial: from 0 to 1000 Hz, alveolar: from 1500 to 2000 Hz, velar: from 1050 to 1499 Hz, palatal velar: from 2001 to 3500. Polynomic best-fits yielded the following classification rates: bilabial: 81.96%. dental: 72.06%. velar: 81.63%. We believe this to be enough to consider the reality of the Haskins locus concept, and also to suggest that polynomic equations are capable of illustrating acoustic invariance.