VOT and hearing impairment
Harlan L. Lane, Joseph S. Perkell · The Journal of the Acoustical Society of America · 2004
When deafened adults recover some hearing after receiving a cochlear implant, numerous changes in their speech occur at both phonemic and suprasegmental levels. If a change toward normative values is observed for some phonemic parameter, it may be attributed to the restored hearing; however, it may be a by-product of a suprasegmental change. Consistent with results reported for speakers with normal hearing, Lane et al. [J. Acoust. Soc. Am. 98, 3096–3106 (1995)] observed in implant users that VOT varies approximately linearly with syllable duration. Therefore, in comparing pre- and postimplant measures of VOT in five speakers, each token’s VOT was adjusted for the change in syllable duration of that token relative to the mean syllable duration in a baseline session (called VOTc). Preimplant, the deaf speakers characteristically uttered plosives with abnormally short VOTc. With some hearing restored, four of the five lengthened VOTc. Changes in voiced plosives’ VOTc with restored hearing were correlated with changes in SPL. Some of the reliable VOTc increases that were not correlated with SPL may have been caused by auditory validation of an internal model for phoneme production. Recent studies of VOT in hearing-impaired speakers will be reviewed in this light. [Work supported by NIDCD, NIH.]