Speech processing under effortful listening conditions in a first and second language in younger and older bilinguals

尽管人口老龄化和语音理解的重要性，影响双语者语音感知的因素研究不足，几乎没有什么是已知的第二语言（L2）的语音处理在老年人。 在第一语言或母语（L1）中，语音理解需要一组复杂的过程，这些过程将退化的声学输入映射到存储的语音和词汇信息的表示上，并将该信息与长期知识相结合。当听到不完美的信号时，需要额外的认知资源（言语工作记忆[WM]，认知控制，高阶语言信息）来理解语音。 ** 这个任务对于一个双语听众来说更难，因为他的语音能力较差，词汇和句法知识也较低。 双语者的二语能力各不相同，二语习得年龄和熟练程度等因素起着重要作用。** 我的NSERC DG计划将缩小文献中的关键差距。我将研究L2句子的理解，在大样本的年轻和老年人的英法双语与一系列的L2能力。我将使用阻碍（语音掩蔽）或促进（上下文，视觉线索）听力的条件，我将考虑一整套自上而下的认知资源的个人措施。我将测量行为，使用神经活动的处理阶段，以及倾听努力的评级。** 研究主题1将使用事件相关脑电位（ERPs; N400）和由上下文约束不同的句子诱发的时频EEG来检查噪声中的言语感知。 我将确定听众在多大程度上使用语境线索来整合第二语言中的单词，这是如何受到听力条件的影响，这是否随年龄而变化，以及模式是否受到认知能力和听力努力的个体差异的调节。研究主题2将考察视听（AV）语音线索促进第二语言句子加工的程度。 我将检查自下而上（视觉/听觉敏锐度，视位和音素感知）和自上而下的因素（上下文，WM，处理速度）。 研究1将探讨这些因素作为双语者感知句子在单峰（视觉和视觉）和双峰（AV）条件下在L1和L2。 我将确定双语者在多大程度上受益于第二语言中的AV语音提示，而不是他们在第一语言中利用这些提示的能力。 然后，研究2将测试AV语音提示是否有益于L2口头WM。这项研究将产生变革性的影响，通过产生一个全面的第二语言语音理解模型，考虑到复杂的听力条件和个体差异。考虑到许多因素影响听力（噪音、电信期间的语音退化、老年性耳聋等），这项工作将与加拿大人的日常生活密切相关。

Despite an aging population and the importance of speech understanding, the factors that influence speech perception in bilinguals are understudied and virtually nothing is known about second language (L2) speech processing in older adults. In a first or native language (L1), speech understanding requires a complex set of processes that map degraded acoustic inputs onto stored representations of phonological and lexical information and integrate that information with long-term knowledge. When listening to an imperfect signal, additional cognitive resources (verbal working memory [WM], cognitive control, higher-order language information) are needed to understand speech. ******This task is even harder for a bilingual listener who has imperfect knowledge due to poorer phonological competence and lower vocabulary and syntactic knowledge in L2. Bilinguals vary in L2 competence, with factors such as L2 age of acquisition and proficiency playing important roles. ******My NSERC DG program will close critical gaps in the literature. I will examine L2 sentence understanding in large samples of younger and older English-French bilinguals with a range of L2 competence. I will use conditions that impede (phonological masking) or facilitate (context, visual cues) listening, and I will consider a full set of individual measures of top-down cognitive resources. I will measure behaviour, stages of processing using neural activity, and ratings of listening effort. ******Research Theme 1 will examine speech perception in noise using event-related brain potentials (ERPs; N400) and time-frequency EEG evoked by sentences varying in contextual constraint. I will determine the degree to which listeners use contextual cues to integrate words in L2, how this is influenced by listening condition, whether this differs with age, and whether patterns are moderated by individual differences in cognitive ability and listening effort.******Research Theme 2 will examine the extent to which audiovisual (AV) speech cues facilitate sentence processing in L2. I will examine bottom-up (visual/hearing acuity, viseme and phoneme perception) and top-down factors (context, WM, processing speed). Study 1 will examine these factors as bilinguals perceive sentences in unimodal (visual- and auditory-only) and bimodal (AV) conditions in L1 and L2. I will determine the extent to which bilinguals benefit from AV speech cues in L2, over and above their ability to exploit these cues in L1. Study 2 will then test if AV speech cues benefit L2 verbal WM.******This research will have a transformative impact by producing a comprehensive model of L2 speech understanding that accounts for complex listening conditions and individual differences. Given that many factors influence listening (noise, degraded speech during telecommunication, presbycusis, etc.), this work will have considerable relevance to the lives of everyday Canadians.