Occurrence Frequencies of Acoustic Patterns of Vocal Fry in American English Speakers.

OBJECTIVE: The goal of this study was to analyze the occurrence frequencies of three individual acoustic patterns (A, B, C) and of vocal fry overall (A + B + C) as a function of gender, word position in the sentence (Not Last Word vs. Last Word), and sentence length (number of words in a sentence). STUDY DESIGN: This is an experimental design. METHODS: Twenty-five male and 29 female American English (AE) speakers read the Grandfather Passage. The recordings were processed by a Matlab toolbox designed for the analysis and detection of creaky segments, automatically identified using the Kane-Drugman algorithm. The experiment produced subsamples of outcomes, three that reflect a single, discrete acoustic pattern (A, B, or C) and the fourth that reflects the occurrence frequency counts of Vocal Fry Overall without regard to any specific pattern. Zero-truncated Poisson regression analyses were conducted with Gender and Word Position as predictors and Sentence Length as a covariate. RESULTS: The results of the present study showed that the occurrence frequencies of the three acoustic patterns and vocal fry overall (A + B + C) are greatest at the end of sentences but are unaffected by sentence length. The findings also reveal that AE female speakers exhibit Pattern C significantly more frequently than Pattern B, and the converse holds for AE male speakers. CONCLUSIONS: Future studies are needed to confirm such outcomes, assess the perceptual salience of these acoustic patterns, and determine the physiological correlates of these acoustic patterns. The findings have implications for the design of new excitation models of vocal fry.

Prevalence of vocal fry in young adult male American English speakers.

The purpose of this study was to assess possible gender differences in the prevalence of vocal fry in the voices of young male college students. Results were compared with previously published findings derived from a matched sample of female speakers. Thirty-four male college students, native American English speakers, produced speech samples in two speaking conditions: (1) sustained isolated vowel /a/ and (2) reading task. Data analyses included perceptual evaluations by two licensed speech-language pathologists. Results showed that vocal fry was perceived significantly more frequently in sentences than in isolated vowel productions. When vocal fry occurred in sentences, it was detected significantly more often in sentence-final position than in initial- and/or mid-sentence position. Furthermore, the prevalence of vocal fry in sentences was significantly lower for male speakers than has previously been reported for female speakers. Possible physiological and sociolinguistic explanations are discussed.

Habitual use of vocal fry in young adult female speakers.

The purpose of this study was to examine the use of vocal fry in young adult Standard American-English (SAE) speakers. This was a preliminary attempt (1) to determine the prevalence of the use of this register in young adult college-aged American speakers and (2) to describe the acoustic characteristics of vocal fry in these speakers. Subjects were 34 female college students. They were native SAE speakers aged 18-25 years. Data collection procedures included high quality recordings of two speaking conditions, (1) sustained isolated vowel /a/ and (2) sentence reading task. Data analyses included both perceptual and acoustic evaluations. Results showed that approximately two-thirds of this population used vocal fry and that it was most likely to occur at the end of sentences. In addition, statistically significant differences between vocal fry and normal register were found for mean F(0) minimum, F(0) maximum, F(0) range, and jitter local. Preliminary findings were taken to suggest that use of the vocal fry register may be common in some adult SAE speakers.

Voicing and devoicing assimilation of French /s/ and /z/.

The present acoustic-phonetic study explores whether voicing and devoicing assimilations of French fricatives are equivalent in magnitude and whether they operate similarly (i.e., complete vs. gradient, obligatory vs. optional, regressive vs. progressive). It concurrently assesses the contribution of speakers' articulation rate to the proportion of voicing (i.e., voicing ratios) in /s/ and /z/ embedded in fricative#stop sequences. Data analyses show that voicing and devoicing assimilation are similar in many regards: the absolute amounts of voicing change are equivalent in magnitude (0.77, 0.78) for the two processes: changes in voicing ratios are accompanied by changes in fricative and preceding vowel durations. These concomitant alterations result in the increased acoustic-phonetic similarity between the assimilated and the non-assimilated forms, suggesting that the two processes might be complete. In addition, the two processes operate regressively and across word-boundary. However, data show that the voicing assimilation of /s/ is not rate dependent, which suggest that it might be obligatory, while the devoicing assimilation of /z/ is rate dependent, which suggest that it might be optional.

The stop voicing contrast in French sentences: contextual sensitivity of vowel duration, closure duration, voice onset time, stop release and closure voicing.

This study examined the manner in which French speakers used some acoustic correlates to produce the stop voicing distinction in French sentences when syllables containing syllable initial and -final stops were between vowels (/pa_a/) and between voiceless fricatives (/pas_s/). Data analyses revealed that /b, d, g/ were longer, were more frequently phonated, and were preceded by longer vowels than /p, t, k/ in three conditions: syllable-initial stops between vowels and between voiceless fricatives and syllable-final stops between vowels. When a voiceless fricative /s/ followed /b, d, g/, the voicing contrast was reduced as a result of complete regressive voicing assimilation, achieved by the concomitant devoicing of /b, d, g/ closures and the significant reduction in voicing-related differences in preceding vowel and closure durations. When /s/ preceded /b, d, g/, the voicing distinction was enhanced: significant voicing-related duration differences were accompanied by the complete assimilation of /s/ to [z]. Overall, findings suggest that in French sentences, voicing assimilation is strictly regressive and complete assimilation is achieved by the covariation of several acoustic correlates, which attests to the complementarity of the underlying articulatory gestures.