Sentence final fricative spectrum variation as a function of prosodic context

Abstract

The spectra of word final [s] in /CVCs/ words (where V is one of {a i o u} and C2 one of {k t}) in sentence final position for questions and statements produced by female talkers were compared. The results indicate that the frequency of peak spectral energy in the [s] was higher for questions than for statements by several hundred hertz. The difference in spectra was generally greater following /k/ than following /t/. The expected lower-frequency spectral energy was observed following the back vowels /o u/, despite the intervening consonant. These results are consistent with Honda's (1983) hypothesis of a biomechanical interaction between supralaryngeal articulation and laryngeal F0 control. Honda suggests a “supplementary tensor mechanism” by which genioglossus and geniohyoid activity displaces the hyoid bone forward and hence rotates laryngeal structures. By the same token, increased tension of the vocal folds may require modification of the shape of the upper vocal tract. It is proposed that the supplementary tensor mechanism facilitates F0 raising during a question final rise. Increased tongue fronting, especially during a /k-s/ sequence, results in a smaller resonating cavity for /s/ and therefore higher-frequency energy distribution during the /s/ for questions than for statements. [Work supported by NIDCD grant DC-00016 and MH41511.]