Greek fricatives: Inferring articulation from F2 at vowel onset

Abstract

Fricative consonants are produced with a narrow constriction in the vocal tract. According to the acoustic theory of speech production (Fant, 1960), fricatives are characterized by spectral prominences corresponding to the natural frequencies of the cavity anterior to the constriction. The spectral characteristics may also be modified by acoustic coupling of the noise source to the cavity behind the constriction (Stevens, 1998). In addition to the defining acoustic attributes, other articulatory gestures may be added to enhance the perceptual saliency of the fricatives (Stevens, 1989). This study examines the second formant frequency (F2) at the onset of a vowel following a fricative as an indication of tongue body position, a potential enhancing gesture for fricatives. F2 measurements were obtained from a database of 1950 tokens including all ten Greek fricatives (five places of articulation, two voicing categories) produced in five vowel contexts by 25 speakers. The results indicate highest F2 for palatals, followed by alveolars, dentals, labiodentals, and velars. Despite some variability by vowel context, the F2 values are reliably distinct among the five places of articulation. These findings are discussed in terms of the acoustic theory and the enhancement account.