Doctoral Dissertation Research: Processing foreign-accented speech in noisy conditions in children and adults

在当今全球化的世界里，人们越来越多地遇到带有外国口音的人：例如，世界上大多数说英语的人都不是母语人士。此外，自然语言交流很少发生在理想的听力条件下，我们经常在被背景噪音包围的情况下听别人说话。因此，在嘈杂的背景下处理和理解外国口音已经成为日常交流的一个共同特征。对于学龄儿童来说也是如此，因为他们的同龄人可能会说外国口音，他们的教室可能会很嘈杂。先前的语言学研究表明，背景噪音的增加会影响对外国口音语音的理解，而不是对母语口音语音的理解，并且已经提出了认知需求增加的可能解释。本项目结合行为和神经认知（EEG）技术，测量了句子加工过程中的认知需求，以检验三个问题：(1)成人和(2)儿童在背景噪音和安静条件下处理外国口音和本土口音句子的语言认知机制是什么？(3)在背景噪音和安静环境中呈现的母语和外国口音句子中，对语义异常的行为和神经反应的个体差异的潜在来源是什么？两个年龄组将在两个实验中进行测试：年轻人和9-11岁的儿童。在EEG任务中，参与者听母语和外国口音的英语句子。每种重音条件下的一半句子将嵌入背景噪声中，其余句子将嵌入静音中；一半的句子将包含语义异常，一半将是语义良好的。参与者还将完成一份语言背景调查问卷，报告人口统计信息、语言使用、熟练程度和口音，以及衡量个人语言和认知能力差异的行为任务。本项目为嘈杂和安静环境下外语口音和母语口音语音处理的认知和神经基础提供了基础见解。研究结果还具有现实意义，例如，可以为教育工作者提供在教室中促进最佳学习环境的信息。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 today's globalized world, people increasingly encounter speakers with a foreign accent: the majority of English speakers across the world, for example, are non-native speakers. Moreover, natural speech communication rarely takes place in ideal listening conditions and we often listen to others when surrounded by background noise. Processing and comprehending foreign-accented speech in noisy backgrounds has thus become a common characteristic of everyday communication. This is also true for school-aged children, as their peers may be foreign-accented speakers and their classrooms can be noisy. Prior linguistic research has demonstrated that the addition of background noise can impact the understanding of foreign-accented speech, more so than native-accented speech, and increased cognitive demand has been proposed as the possible explanation. This project measures cognitive demands during sentence processing, combining behavioral and neurocognitive (EEG) techniques, to examine three questions: What are the linguistic-cognitive mechanisms underlying the processing of foreign-accented and native-accented sentences embedded in background noise and in quiet conditions in (1) adults and (2) children? (3) What are potential sources of individual variability in behavioral and neural responses to semantic anomalies in native- and foreign-accented sentences presented in background noise and in quiet? Two age groups will be tested in two experiments: young adults and children aged 9-11. In the EEG task, participants listen to native- and foreign-accented English sentences. Half the sentences in each accent condition will be embedded in background noise, and the remaining sentences in quiet; half the sentences will contain semantic anomalies and half will be semantically well-formed. Participants will also complete a language background questionnaire, reporting demographic information, language use, proficiency, and accent exposure, as well as behavioral tasks measuring individual differences in linguistic and cognitive abilities. This project provides foundational insights on the cognitive and neural bases of foreign- and native-accented speech processing in noisy and quiet environments. The outcomes also have real-life implications and can, for example, inform educators on facilitating optimal learning environments in their classrooms.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.