Doctoral Dissertation Research: Nonnative Phonetic Perception in Adult L2 Learners

即使经过多年的练习，成年学习者在第二语言（L2）中感知和发出声音方面也有困难。与儿童相比，成年人往往需要更有针对性和更有针对性的输入来实现类似母语的第二语言声音感知和产生。本文旨在阐明第二语言感知受第一语言（L1）声音影响的机制，这种感知的神经基础，学习者差异如何影响学习，以及不同的训练范式如何调节L2声音感知的神经和行为基础。这项工作有可能明确哪些机制影响L2声音感知，以及不同类型的反馈和指导如何帮助学习者更好地感知差异，从而在课堂和沉浸式环境中更好地进行L2教学。参加为期五天的训练模式，在此期间，他们将学习区分不属于他们的L1声音类别的印地语声音。在五天的时间里，参与者将完成头皮脑电图（EEG）记录、基线辨别任务、培训以及几项记忆和注意力个人测量。研究人员预计，L1将在声音开始后约150- 200 ms调制EEG波形，称为失配负波（MMN）。该测量指标指示早期语音学习，并且先前的研究已经表明波形的幅度可以随着新的语音学习而改变或移位，这表明早期声学和语音处理随着新的输入而重组。此外，研究人员将研究如何L1和不同的培训和反馈范式影响这种MMN的变化。这些分析将突出以前未探索的L2行为和神经处理的差异，产生于先前的L1知识和表征。此外，最后的分析将通过将行为训练期间的表现与神经反应相关联来将行为和神经措施联系起来，以调查成人第二语言语音习得的时间过程。本研究从行为和神经两个方面探讨了母语对非母语语音感知的影响（这是第一个考察和阐明语音习得时间进程的训练范式），为二语语音感知和习得的模型提供了有价值的信息，也为二语语音对比的教学提供了相关的数据。

Even with years of practice, adult learners have trouble perceiving and producing sounds in a second language (L2). Adults tend to need more focused and targeted input to achieve native-like perception and production of L2 sounds than do children. The work proposed here aims to clarify the mechanisms through which L2 perception is influenced by first language (L1) sounds, the neural basis of this perception, how learner differences can influence learning, and how different training paradigms modulate both the neural and behavioral basis of L2 sound perception. This work has the potential to clarify specifically what mechanisms affect L2 sound perception and how different types of feedback and instruction can help learners perceive differences better, allowing for better L2 instruction in the classroom and immersion settings.This study will have participants from two native speaker groups, English and Spanish, participate in a five-day training paradigm during which they will learn to discriminate Hindi sounds that do not belong to their L1 sound categories. During the five days, participants will come in to complete electroencephalogram (EEG) recordings from the scalp, baseline discrimination tasks, training, and several memory and attention individual measures. The researchers expect that the L1 will modulate the EEG waveform known as the mismatch negativity (MMN) at approximately 150-200ms after sound onset. This measure indexes early phonetic learning and previous research has shown that the waveform's amplitude can change or shift with new phonetic learning, indicating a reorganization of early acoustic and phonetic processing with new input. Furthermore, the researchers will examine how the L1 and different training and feedback paradigms influence this MMN change. The analyses will highlight previously unexplored differences in L2 behavioral and neural processing that arise from prior L1 knowledge and representations. Furthermore, final analyses will link behavioral and neural measures by correlating performance during behavioral training with neural responses to investigate the time course of adult L2 phonetic acquisition. By using both behavioral and neural methods to explore the effects of L1 influence on nonnative phonetic perception (in the first such training paradigm to examine and clarify the time course of phonetic acquisition), this work will contribute valuable information for models of L2 perception and acquisition, and relevant data for the instruction and teaching of L2 sound contrasts.