Phoneme confusions as a function of age

Initial and final consonant confusions in a variety of vowel environments were studied as a function of age from 20–69 years in decades using the CUNY Nonsense Syllable Test [Resnick, S. B. et al., Asha 18, 651, (1976)]. In terms of number of errors, the effects of age, level, and subset were significant. More errors were made by the elderly. Results obtained at MCL and MCL + 8 dB were not significantly different; and these were significantly better than at MCL − 8 dB. Subset differences revealed that vowel environment affected final unvoiced consonant recognition in a systematic manner: Fewest errors were associated with /u/ and the greatest number with /i/; errors associated with /a/ falling between these. This was true for young and old alike. Combined error matrices revealed that confusions made by young listeners were essentially between acoustically similar phonemes and tended to cluster (/θ ↔ f/, /δ ↔ v/). Interestingly, the direction of confusion tended to be vowel dependent. For the elderly, confusions were far more diffuse with far less tendency toward clustering among particular phonemes. The implications are discussed. [Work supported by VA.]