Sex-Related Acoustic Changes in Voiceless English Fricatives

Abstract

This investigation is a comprehensive acoustic study of 4 voiceless fricatives (/f theta s /) in English produced by adults and pre- and postpubescent children aged 6-14 years. Vowel duration, amplitude, and several different spectral measures (including spectral tilt and spectral moments) were examined. Of specific interest was the pattern of normal development of the acoustic properties of fricatives and the nature of sex-specific patterns of fricative articulation in prepubescent children. Little evidence of amplitude or duration differences was found between speakers that was related to sex of the speaker. However, significant sex-specific differences in fricative articulation were found in all groups of speakers-even in the youngest children (ages 6-7 years)-although there was an indication that some of the acoustic differences between females and males is reduced or absent in the youngest children. Results from discriminant analysis demonstrated that a discriminant function based on the adult male tokens was generally better at classifying fricatives produced by male speakers than female speakers, regardless of age. This showed that sex-related differences (presumably a function of sex-linked vocal tract variation) were present even in the youngest speaker group. However, the classification accuracy of the female model showed a steady improvement with the increased age of the female speakers and may provide support for the claim that sex-related developmental differences may just be emerging in the youngest age group.

Production of contrast between sibilant fricatives by children with cochlear implants

“…This result supports the claim that the children with CIs produced /s/ with lower spectral peaks than the children with NH in the hearing age comparison because of differences in auditory perceptual abilities rather than differences in vocal tract size. The difference in the effect of age on spectral peaks of productions of /s/ and /$/ is consistent with results of Fox and Nissen (2005) who found that over a much larger age range, age explained more of the variability in spectral peak locations of /$/ than of /s/. Uchanski and Geers (2003) and Liker et al (2007) similarly noted that children with CIs produced reduced contrast between /s/ and /$/ due to the production of /s/ at lower frequencies.…”

“…Since the children with CIs were older than the children with NH in the hearing age comparison, it was worth investigating whether the difference in /s/ production between the children with CIs and these children with NH was due to differences in vocal tract size. Previous studies have found that children produce fricatives at higher frequencies than adults (Nittrouer, 1995;Fox and Nissen, 2005). This is consistent with the fact that children have smaller vocal tracts than adults, and therefore their fricative productions resonate at higher frequencies.…”

“…Thus from changes in the spectral mean, it is difficult to know which articulatory changes took place. A measure of the frequency of the highest spectral peak can also differentiate /s/ and /$/ (Jongman et al, 2000;Fox and Nissen, 2005). This measure tends to relate to articulation in that it can be an indicator of the size of the cavity in the vocal tract anterior to the constriction.…”

Language specificity in the perception of voiceless sibilant fricatives in Japanese and English: Implications for cross-language differences in speech-sound development

“…Therefore, the M1 value of /s/ is expected to be higher than that of /$/ because of the shorter front resonating cavity in /s/. This prediction has been confirmed robustly in many acoustic studies of English fricatives (Forrest et al, 1988;Jongman, et al, 2000;Nissen and Fox, 2005;Nittrouer, 1995;Shadle and Mair, 1996;Fox and Nissen, 2005).…”

“…Miccio et al (1996) found all four moments are effective in describing the /s/-/$/ distinctions produced by normal developing children. Similarly, Nissen and Fox (2005) and Fox and Nissen (2005) also utilized spectral moments analysis to describe fricative productions by children, adolescents, and adults. They found that all four moments are useful in describing children's /s/ and /$/ distinctions and the two sounds are better distinguished acoustically as children's ages increase.…”