Speech perception requires accommodation of a wide range of acoustic variability across talkers. A classic example is the perception of "sh" and "s" fricative sounds, which are categorized according to spectral details of the consonant itself, and also by the context of the voice producing it. Because women's and men's voices occupy different frequency ranges, a listener is required to make a corresponding adjustment of acoustic-phonetic category space for these phonemes when hearing different talkers. This pattern is commonplace in everyday speech communication, and yet might not be captured in accuracy scores for whole words, especially when word lists are spoken by a single talker. Phonetic accommodation for fricatives "s" and "sh" was measured in 20 cochlear implant (CI) users and in a variety of vocoder simulations, including those with noise carriers with and without peak picking, simulated spread of excitation, and pulsatile carriers. CI listeners showed strong phonetic accommodation as a group. Each vocoder produced phonetic accommodation except the 8-channel noise vocoder, despite its historically good match with CI users in word intelligibility. Phonetic accommodation is largely independent of linguistic factors and thus might offer information complementary to speech intelligibility tests which are partially affected by language processing.
Bibliographical noteFunding Information:
Data collection for this study was funded by NIH-NIDCD R01 DC 004786 (M. Chatterjee), R01 DC003083 (R. Litovsky), and NIH-NIDCD: R03 DC014309 (M.B.W.). Additional support was provided by a core grant to the Waisman Center from the NIH-NICHD (Grant No. P30 HD03352). Data from the first seven CI listeners were collected with the support of the University of Maryland Center for Comparative and Evolutionary Biology of Hearing Training Grant T32 DC000046-17 (A. Popper). M.B.W. was also supported by the NIH division of loan repayment. Brianna Vandyke, Ashley Moore, Tiffany Mitchell, and Steven Gianakas assisted with data collection. Deniz Başkent, Ashley Moore, Tanvi Thakkar, and Alan Kan and three anonymous reviewers contributed helpful comments to an earlier version of this manuscript. 1
© 2020 Acoustical Society of America.
PubMed: MeSH publication types
- Journal Article
- Research Support, N.I.H., Extramural