The characteristics of voicing in syllable-initial fricatives in American English.

This study investigated the acoustic characteristics of voicing in the production of fricative consonants. The fricatives [f v s z] were used in combination with the vowels [i e a o u] to create CV syllables, which were produced by four subjects both in a context condition (following voiced and voiceless velar stops) and in isolation. Analyses were conducted of the time course of glottal excitation during the fricative noise interval in the voiced and voiceless fricative stimuli. Results showed that the patterns of voicing in the fricative noise interval were influenced by the voicing characteristics of preceding stop consonants. Nonetheless, these carryover coarticulatory effects were short-lived, influencing only the first 10's of ms of the following segment. Despite the influence of phonetic context on the patterns of voicing, an acoustic measure relating to the presence or absence of glottal excitation at the acoustic boundaries of the fricative noise reliably classified a majority (93%) of the fricative consonants in terms of the phonetic category of voicing. Thus, while phonetic context affected the patterns of glottal excitation in the fricative noise interval, it did not affect the criterial attribute associated with the phonetic category of voicing.