Children's phoneme identification in reverberation and noise

This study assessed the effects of reverberation, noise, and their combinat ion on listeners' identification of consonants and vowels in naturally prod uced nonsense syllables presented at different sensation levels (re: speech recognition threshold). A secondary purpose of this study was to assess li steners' identification of voicing, manner, and place of articulation For c onsonants at 50 dB SL in the reverberation, noise, and combined conditions. Listeners, aged 6-30 years, identified consonant-vowel-consonant-vowel (CV CV) stimuli presented at Four different sensation levels (re: speech recogn ition threshold) of 30, 40, 50, and 60 dB SL in 4 listening conditions: (a) an optimal listening situation (no reverberation, no noise), (b) reverbera tion only (1.3 seconds), (c) noise only (+ 13 dB S/N against a multitalker babble), and (d) reverberation plus noise. Results showed that all listener groups achieved maximum consonant identification performance at 50 dB SL. Vowel identification scores were unaffected by SL. Statistical analyses rev ealed that children's ability to identify consonants varied according to li stening condition. For example, children's consonant identification abiliti es reached adult-like levels of performance at about age 14 years in the re verberation-only and noise-only listening conditions. However, in the rever beration-plus-noise listening condition, children's consonant identificatio n abilities do not mature until the late teenage years. The ability to iden tify vowels, on the other hand, develops much earlier. A feature analysis o f the consonant data showed that For all 3 features (voicing, manner, and p lace), identification scores were highest in the control condition, similar For the reverberation-only and noise-only conditions, and lowest in the re verberation-plus-noise condition. Voicing was easier For listeners to ident ify than manner or place of articulation features in reverberation and nois e. Taken together, these results suggest that the ability to identify speec h in reverberation and noise reaches adult-like level of performance at dif ferent ages for different components of the speech signal.