Listening effort and multilingual speech communication: Neural measures of auditory and lexical processing by adults and older children

当用第二语言交流时，人们觉得他们需要“更努力地倾听”，但目前还不清楚这种努力如何改变与识别语音有关的大脑过程。我们最初的研究产生了一个令人惊讶的发现;我们测试了那些试图在嘈杂的背景下听说话者说话的人（即，他发现，当人们在听第二种语言时，大脑的听觉区域比听第一种语言时更能分辨出目标说话者。我们通过记录神经活动（脑电图; EEG）并测量它是如何被语音的声学所吸引的来做到这一点。虽然人们通常会被期望在听他们的第一语言时表现得更好，但我们认为第二语言的听众有更多的选择性听觉处理，因为他们额外的听力努力。我们在同一任务中发现了单词识别的神经措施的相关影响，并认为我们已经找到了允许第二语言学习者部分补偿其语音识别困难的机制。在这个赠款项目中，我们将扩大我们的调查在一系列的研究，操纵语音的声学，并比较语音是如何识别在第一和第二语言的英语和韩语的发言者。此外，我们还将测试在儿童时期同时学习这两种语言的成年人，在以后学习第二语言的成年人，以及正在学习这两种语言的年龄较大的儿童。我们的目标是了解人们如何利用听力努力来弥补他们在第二语言演讲中的困难，并研究这种能力如何发展以及与熟练程度的关系。这项工作对于理解人们在日常言语交际中如何应用他们的语言过程和结构非常重要，并且与广泛的困难听力条件（例如，听力障碍）。这项工作也将推进我们对语音神经夹带的新措施如何与语音识别的实际方面相关的科学理解。

People feel like they need to "listen harder" when communicating in a second language, but it isn't clear how this effort changes the brain processes involved in recognising speech. Our initial research has produced a surprising finding; we tested people who were trying to listen to a talker in a noisy background (i.e., a distracting talker), and found that auditory areas of the brain are better at picking out the target talker when people are listening to a second language than their first language. We did this by recording neural activity (electroencephalography; EEG) and measuring how it becomes entrained to the acoustics of speech. Although people would normally be expected to perform better when listening to their first language, we think that second-language listeners had more selective auditory processing because of their additional listening effort. We found related effects for neural measures of word recognition in the same task, and think that we've found mechanisms that allow second-language learners to partially compensate for their speech recognition difficulties. In this grant project, we will expand our investigation in a series of studies that manipulate the acoustics of speech, and compare how speech is recognised in first and second languages by speakers of English and Korean. Furthermore, we will test adults who learned both languages at the same time when they were young children, adults who learned their second language later in life, and older children who are in the process of learning both languages. Our goals are to understand how people can use listening effort to compensate for their difficulties with second-language speech, and examine how this ability develops and relates to proficiency. This work is important for understanding how people apply their processes and structures for language during everyday speech communication, and is relevant to a wide range of difficult listening conditions (e.g., hearing impairment). The work will also advance our scientific understanding of how new measures of neural entrainment for speech relate to practical aspects of speech recognition.