Doctoral Dissertation Research: Investigation of second language lexical representation and processing of Mandarin tones

汉语普通话作为中华人民共和国的国语，在现代世界中具有明显的重要性。因此，我们对如何更有效地学习普通话的理解的进步是美国的国家利益。普通话是一种词汇声调语言，音节上的音高线索区分单词。学习词汇声调对英语母语者来说是一件困难的事情，然而，学习者在学习的最初阶段并不了解学习词汇声调的困难及其原因。本研究主要探讨两个问题：第一，成人第二语言学习者对普通话声调的心理表征是什么样的？第二，学习者在实时单词识别过程中遇到的困难的性质是什么？第一组实验将使用准确性和反应时间的行为测量来推断听众对特定普通话声调（声调3）及其变体（异调）的心理表征的质量。如果学习者对声调3的一种变体的反应不太准确或较慢，这可能表明他们的感知存在偏差，可能是由于只强调声调3的一种形式的常见教学实践。第二组实验将检查事件相关电位（ERP）和行为决定对口语的普通话单词。具体来说，研究将检查N400对单词和非单词的反应，并将其与随后的行为决定进行比较。虽然以前的行为研究表明，学习者对双音节词中的音调的敏感性严重下降，但这项新研究将提供学习者对音调反应的实时证据，可能揭示行为决策中没有捕捉到的敏感性。研究结果将有助于我们理解成人第二语言学习者的词汇声调习得，并可能导致普通话和其他声调语言的学习和教学的改进。

As the national language of the People's Republic of China, Mandarin Chinese has obvious importance in the modern world. Progress in our understanding of how Mandarin can be learned more effectively is thus of national interest for the United States. Mandarin is a lexical tone language, where pitch cues on syllables distinguish words. Learning lexical tones is known to be difficult for native speakers of English, however, the nature of the difficulty and its causes are not well understood beyond the earliest stages of learning. This project will address two main questions: First, what are adult second language learners' mental representations of Mandarin tone categories like? Second, what is the nature of the difficulty learners have during real-time word recognition?A first set of experiments will use behavioral measures of accuracy and response time to make inferences about the quality of listeners' mental representations for a specific Mandarin tone (Tone 3) and its variants (allotones). If learners' responses are less accurate or slower for one variant of Tone 3, this may indicate a bias in their perception, potentially due to common teaching practices that emphasize only one form of Tone 3. A second set of experiments will examine event-related potentials (ERPs) and behavioral decisions in response to spoken Mandarin words. Specifically, research will examine the N400 response to words and nonwords and compare it to the behavioral decisions that follow. While previous behavioral research suggests learners have severely decreased sensitivity to tones in disyllabic words, this new research will provide real-time evidence of learners' responses to tones, potentially revealing sensitivity that is not captured in behavioral decisions. Results will contribute to our understanding of the acquisition of lexical tones by adult second language learners and may lead to improvements in learning and teaching of Mandarin and other tone languages.