Age and hearing loss and the use of acoustic cues in fricative categorization

This study examined the use of fricative noise information and coarticulatory cues for categorization of word-final fricatives [s] and [f] by younger and older Dutch listeners alike. Particularly, the effect of information loss in the higher frequencies on the use of these two cues for fricative categorization was investigated. If information in the higher frequencies is less strongly available, fricative identification may be impaired or listeners may learn to focus more on coarticulatory information. The present study investigates this second possibility. Phonetic categorization results showed that both younger and older Dutch listeners use the primary cue fricative noise and the secondary cue coarticulatory information to distinguish word-final [f] from [s]. Individual hearing sensitivity in the older listeners modified the use of fricative noise information, but did not modify the use of coarticulatory information. When high-frequency information was filtered out from the speech signal, fricative noise could no longer be used by the younger and older adults. Crucially, they also did not learn to rely more on coarticulatory information as a compensatory cue for fricative categorization. This suggests that listeners do not readily show compensatory use of this secondary cue to fricative identity when fricative categorization becomes difficult.