Listener sensitivity to talker differences in phonetic properties of speech

描述（由申请人提供）：该研究的目标是扩展我们对单词识别的早期阶段的认识，在这个阶段，听者从语音信号中提取单个片段。长期以来强调语言表征的抽象本质的言语感知理论，最近受到了一些发现的挑战，这些发现表明，说话者特有的语音信息保留在记忆中，可以促进单词识别。这些发现提出了一种可能性，即详细的声学-语音信息可以用于在说话者特定的基础上定制信号和片段表示之间的映射。为了支持这一说法，现在有证据表明，听者可以追踪特定说话者的声学-语音特性。其中一个特性是语音起始时间（VOT），这是语音的一种时间特性，它标志着顿音辅音的发声对比。听者可以在一个单词开头的不发音停顿的语境中学习说话者特有的vot，而且，可以将这些信息转移到一个以相同停顿开头的新单词中。一个基本的问题仍然没有得到解答，那就是对特定于说话人的语音信息进行追踪的表征水平。所提出的研究的具体目的是通过确定听者是根据语音特征还是根据给定的语音段跟踪说话人特定的VOT来解决这个问题。在训练阶段，听者将学习两个说话者如何发出/p/或/k/。语音合成技术将用于操纵两个说话者的vot，使一个说话者的vot较短，另一个说话者的vot较长。在测试阶段，将使用两种选择的强迫选择任务来检查以与训练中使用的相同的无音顿音开头的单词和以不同发音位置的无音顿音开头的单词的转移情况。如果听者在语音特征方面跟踪说话人特定的VOT，那么在/p/上下文中学习到的不发音顿音信息应该转移到/k/上下文中，在/k/上下文中学习到的信息应该转移到/p/。然而，如果听者根据给定的语音段跟踪特定于说话人的VOT，那么转移应该仅限于以训练中使用的相同的不发音停顿开头的单词。本研究将有助于从理论上理解言语感知中的说话者特异性，并支持正常言语和障碍言语识别设备的发展。这种设备目前的一个限制是不能迅速适应说话者在语音生产方面的差异。研究人类如何处理这种类型的语音变化将提供关键信息，以纳入口语的机器识别。

DESCRIPTION (provided by applicant): The goal of the proposed research is to extend our knowledge of the early stages of word recognition in which listeners extract individual segments from the speech signal. Long-standing accounts of speech perception, which emphasized the abstract nature of linguistic representations, have recently been challenged by findings that indicate that talker-specific, acoustic-phonetic information is retained in memory and can facilitate word recognition. These findings raise the possibility that detailed acoustic-phonetic information is used to customize the mapping between signal and segmental representation on a talker- specific basis. In support of this alternative account, there is now evidence that listeners can track acoustic- phonetic properties for a particular talker. One such property is voice-onset-time (VOT), a temporal property of speech that marks the voicing contrast in stop consonants. Listeners can learn a talker's characteristic VOTs in the context of one word-initial voiceless stop and, moreover, can transfer this information to a novel word that begins with the same stop. A fundamental question that remains unanswered concerns the level of representation at which talker-specific, acoustic-phonetic information is tracked. The specific aim of the proposed research is to address this question by determining whether listeners track talker-specific VOT with respect to a phonetic feature or with respect to a given phonetic segment. During a training phase, listeners will learn how two talkers produce /p/ or /k/. Speech synthesis techniques will be used to manipulate the VOTs of the two talkers so that one talker has shorter VOTs and the other talker has longer VOTs. During a test phase, a two-alternative forced-choice task will be used to examine transfer to words that begin with the same voiceless stop as used during training and to words that begin with a voiceless stop at a different place of articulation. If listeners track talker-specific VOT with respect to a phonetic feature, then information learned about voiceless stop consonants in the context of /p/ should transfer to /k/ and information learned in the context of /k/ should transfer to /p/. However, if listeners track talker-specific VOT with respect to a given phonetic segment, then transfer should be limited only to words that begin with the same voiceless stop as used during training. This research will contribute to the theoretical understanding of talker specificity in speech perception as well as support the advancement of devices that recognize normal and disordered speech. One current limitation of such devices is the failure to rapidly adapt to talker differences in speech production. Examining how humans process this type of phonetic variation will provide critical information to incorporate into machine recognition of spoken language.