Department of Spanish Language, University of Málaga, Málaga, Spain.
Department of Communications Engineering, University of Málaga, Málaga, Spain.
PLoS One. 2020 Nov 9;15(11):e0242018. doi: 10.1371/journal.pone.0242018. eCollection 2020.
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).
儿童比成人更早地习得元音，而且前者比后者更不易受言语障碍的影响。本研究探索了一个假设，即在生命后期也存在类似的对比，即辅音比元音更容易受到衰老的影响。本研究使用两个实验来比较年轻成年人（YA）和中年成年人（MA）的语音数据。在第一个实验中，一个自动语音识别（ASR）系统使用一个由 29 名 YA 和 27 名 MA 的平衡语料库进行训练。每个说话者的发音都是在西班牙语单词（W）和非单词（NW）重复任务中获得的。使用交叉验证方法，通过评估系统在训练语料库上的性能来评估系统的性能。该 ASR 系统可以识别出两组说话者的 Ws，识别程度相似，但对于 YA 的 NWs 的识别比 MA 的 NWs 的识别更为成功。详细的错误分析表明，MA 说话者在辅音以及发音方式和发音部位方面的得分低于 YA 说话者；在元音和浊音特征方面，两组说话者的结果几乎相同。在第二个实验中，一组健康的母语听众被要求在背景噪声中识别孤立的音节。目标说话者是在第一个实验中参与的一个 YA 和一个 MA。结果与 ASR 实验的结果一致：在 YA 说话者中，发音方式和发音部位的识别效果更好，而在 MA 说话者中，元音和浊音的识别效果更差。我们得出结论，辅音发音比元音发音更容易受到衰老的影响。未来的研究应该探讨这种发音准确性的早期和选择性变化是否可能是由于言语感知技能的变化（例如，在听觉时间处理方面）引起的。
