Analysis of Spanish consonant recognition in 8-talker babble

Consonant and vowel articulation accuracy in younger and middle-aged Spanish healthy adults

Children acquire vowels earlier than consonants, and the former are less vulnerable to speech disorders than the latter. This study explores the hypothesis that a similar contrast exists later in life and that consonants are more vulnerable to ageing than vowels. Data was obtained with two experiments comparing the speech of Younger Adults (YAs) and Middle–aged Adults (MAs). In the first experiment an Automatic Speech Recognition (ASR) system was trained with a balanced corpus of 29 YAs and 27 MAs. The productions of each speaker were obtained in a Spanish language word (W) and non–word (NW) repetition task. The performance of the system was evaluated with the same corpus used for training using a cross validation approach. The ASR system recognized to a similar extent the Ws of both groups of speakers, but it was more successful with the NWs of the YAs than with those of the MAs. Detailed error analysis revealed that the MA speakers scored below the YA speakers for consonants and also for the place and manner of articulation features; the results were almost identical in both groups of speakers for vowels and for the voicing feature. In the second experiment a group of healthy native listeners was asked to recognize isolated syllables presented with background noise. The target speakers were one YA and one MA that had taken part in the first experiment. The results were consistent with those of the ASR experiment: the manner and place of articulation were better recognized, and vowels and voicing were worse recognized, in the YA speaker than in the MA speaker. We conclude that consonant articulation is more vulnerable to ageing than vowel articulation. Future studies should explore whether or not these early and selective changes in articulation accuracy might be caused by changes in speech perception skills (e.g., in auditory temporal processing).

Recognition of Spanish consonants in 8-talker babble by children with cochlear implants, and by children and adults with normal hearing

This paper presents the results of closed-set recognition task for 80 Spanish consonant-vowel sounds in 8-talker babble. Three groups of subjects participated in the study: a group of children using cochlear implants (CIs; age range: 7-13), an age-matched group of children with normal hearing (NH), and a group of adults with NH. The speech-to-noise ratios at which the participants recognized 33% of the target consonants were +7.8 dB, -3 dB, and -6 dB, respectively. In order to clarify the qualitative differences between the groups, groups were matched for the percentage of recognized syllables. As compared with the two groups with NH, the children with CIs: (1) produced few "I do not know" responses; (2) frequently selected the voiced stops (i.e., /b, d, ɡ/) and the most energetic consonants (i.e., /l, r, ʝ, s, ʧ/); (3) showed no vowel context effects; and (4) had a robust voicing bias. As compared with the adults with NH, both groups of children showed a fronting bias in place of articulation errors. The factors underlying these error patterns are discussed.