Doctoral Dissertation Research: Production and perception of native and non-native speech enhancement

为了使演讲交流成功，演讲者必须能够将他们的信息清楚地传达给听众。例如，当听者不明白说话者第一次说的话时，说话者可以用更清晰的方式重复他们所说的话，以便听者能够理解。这种看似简单的提高听者语言清晰度的行为通常是由流利的语言者自然进行的，然而对于那些说话不太流利和不太容易理解的人来说，比如非母语人士，这可能很难。不被听者理解对非母语人士来说有着非常现实的后果，因为这会大大减少他们获得工作和教育的机会，更广泛地说，会减少他们作为平等成员参与社会的机会。这个问题的重要性被美国非英语母语人口的增长所突出。这个项目旨在通过研究不同语言背景的说话者如何在不同的交流环境中使用语音增强策略来更好地理解为什么在非母语中提高语音清晰度是困难的。这个项目的结果可以为第二语言学习方法的发展提供信息，也可以为临床人群提供干预措施，这些人群可能在提高语言清晰度方面遇到困难。这个项目的目标是了解有助于提高语音清晰度的两个方面：说话者使用什么样的策略来提高他们的语音，以及听者如何感知这些策略。具体来说，拟议的实验考察了说话者清晰说话的能力是如何受到不同来源的影响的，比如说话者的语言背景、说话材料的特征（例如，对单词或短语的熟悉程度）和交际语境的特征。此外，该项目还研究了讲话者提高语音清晰度的努力如何转化为听者对该演讲的感知，包括感知的可理解程度（理解演讲的容易程度）和感知的讲话者努力程度（讲话者试图说清楚的努力程度）。这个项目将帮助我们更好地了解说话者和听者在提高各种母语和非母语人群的语音清晰度方面的贡献。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

In order for speech communication to be successful speakers must be able to deliver their messages clearly to their listeners. For example, when a listener does not understand what was said by a speaker the first time, the speaker may repeat what they said in a clearer manner so that the listener can understand it. This seemingly simple act of enhancing intelligibility of speech for a listener is often carried out naturally by fluent speakers of the language, yet it can be difficult for people who produce less fluent and less intelligible speech, such as non-native speakers of the language. Not being understood by listeners has very real consequences for non-native speakers as it can significantly decrease their opportunities to obtain jobs and education, and more broadly, to participate in society as an equal member. The significance of this issue is highlighted by the growing population of non-native English speakers in the U.S. This project seeks to better understand why it can be difficult to enhance speech intelligibility in a non-native language by examining how speakers of different linguistic backgrounds use speech enhancement strategies in different communication contexts. The results of this project could inform the development of methodologies for second language learning as well as interventions for clinical populations who may experience difficulty enhancing their speech intelligibility. The goal of this project is to understand two aspects of what contributes to enhancing speech intelligibility: what kinds of strategies speakers use to enhance their speech and how these strategies are perceived by listeners. Specifically, the proposed experiments examine how a speaker’s ability to speak clearly is affected by different sources, such as the speaker's language background, characteristics of the speech materials (e.g., familiarity of the words or phrases), and characteristics of the communication context. Further, the project examines how speakers' attempts to enhance speech intelligibility translate to listeners' perception of this speech, including perceived degree of comprehensibility (how easy it is to understand the speech) and perceived degree of speaker effort (how hard the speaker is trying to speak clearly). This project will help us better understand the contributions from both speakers and listeners to enhancing speech intelligibility for a variety of native and non-native speaking populations.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.