Iverson Paul, Hazan Valerie, Bannister Kerry
Department of Phonetics and Linguistics, University College London, 4 Stephenson Way, London NW1 2HE, United Kingdom.
J Acoust Soc Am. 2005 Nov;118(5):3267-78. doi: 10.1121/1.2062307.
Recent work [Iverson et al. (2003) Cognition, 87, B47-57] has suggested that Japanese adults have difficulty learning English /r/ and /l/ because they are overly sensitive to acoustic cues that are not reliable for /r/-/l/ categorization (e.g., F2 frequency). This study investigated whether cue weightings are altered by auditory training, and compared the effectiveness of different training techniques. Separate groups of subjects received High Variability Phonetic Training (natural words from multiple talkers), and 3 techniques in which the natural recordings were altered via signal processing (All Enhancement, with F3 contrast maximized and closure duration lengthened; Perceptual Fading, with F3 enhancement reduced during training; and Secondary Cue Variability, with variation in F2 and durations increased during training). The results demonstrated that all of the training techniques improved /r/-/l/ identification by Japanese listeners, but there were no differences between the techniques. Training also altered the use of secondary acoustic cues; listeners became biased to identify stimuli as English /l/ when the cues made them similar to the Japanese /r/ category, and reduced their use of secondary acoustic cues for stimuli that were dissimilar to Japanese /r/. The results suggest that both category assimilation and perceptual interference affect English /r/ and /l/ acquisition.
近期的研究工作[艾弗森等人（2003年），《认知》，第87卷，B47 - 57页]表明，日本成年人在学习英语/r/和/l/时存在困难，因为他们对那些在/r/-/l/分类中不可靠的声学线索（例如，F2频率）过于敏感。本研究调查了线索权重是否会因听觉训练而改变，并比较了不同训练技术的有效性。不同组的受试者分别接受了高变异性语音训练（来自多个说话者的自然单词），以及3种通过信号处理改变自然录音的技术（全增强，使F3对比度最大化并延长闭塞持续时间；感知衰减，在训练期间降低F3增强；以及次要线索变异性，在训练期间增加F2和持续时间的变化）。结果表明，所有训练技术都提高了日本听众对/r/-/l/的识别能力，但这些技术之间没有差异。训练还改变了对次要声学线索的使用；当线索使刺激与日语/r/类别相似时，听众倾向于将刺激识别为英语/l/，并且减少了对与日语/r/不同的刺激使用次要声学线索。结果表明，类别同化和感知干扰都会影响英语/r/和/l/的习得。
