Neural mechanisms for phonological alternation with high and low productivity - a case study on tone sandhi

在当今世界上使用的大约7,000种语言中，保守估计约有一半是声调语言，因为音高本身的使用可能会改变单词的含义。这份名单包括在美国经济和国家安全中发挥关键作用的语言，如汉语和越南语，以及许多美洲土著语言，如纳瓦霍语和切罗基语。更好地了解这些语言的语言特性是提高与这些语言的使用者的沟通效率和为英语母语者开发更好的学习材料的有意义的第一步。本研究利用最先进的神经语言学技术，探讨两种汉语--普通话和台语--中声调的语言模式，以阐明带声调的单词在说话者大脑中的表现方式。它有助于方法的创新，这将使不同阶段的生产处理的音调被跟踪的神经措施。此外，该项目涉及美国机构与香港和台湾两个著名神经语言实验室之间的国际合作。建立的联系将为美国和国际学生提供教育机会。这个项目的重点是声调交替模式，即一个声调在不同的语境中采取不同的语音形式，也被称为“连读变调”。“行为研究表明，连读变调模式以不同的方式延伸到新单词，即，有不同的生产力，这取决于模式的语音性质。这表明，不同的机制可能涉及在处理这种类型的语音交替。本研究以事件相关电位（ERPs）探讨国语与台语连读变调模式在言语产生过程中的编码时程。据推测，非生产性连读变调模式主要是由一个词汇机制，从事神经活动在较早的时间窗口的词汇检索（约150-225毫秒后开始生产），而生产性连读变调模式主要是由一个计算机制，从事神经活动在较晚的时间窗口的语音编码（400-600毫秒）。此外，我们还假设，词汇机制的神经活动对词频敏感，而计算机制的神经活动则不那么敏感。这个项目将是第一个调查潜在的神经活动的假定计算与词汇机制与生产性和非生产性的语音交替。对语音交替的神经编码的进一步理解将为言语产生的理论模型和语音能力的形式模型提供信息。该项目的研究结果也可以与形态分解的问题联系起来，如规则性和语义透明度，以更全面地了解语言生产力的神经基础。该奖项反映了NSF的法定使命，并被认为值得通过使用基金会的智力价值和更广泛的影响审查标准进行评估来支持。

Of the 7,000 or so languages spoken in the world today, a conservative estimate of around half of them are tonal, in that the use of pitch itself may change the meaning of a word. This list includes languages that play key roles in the economy and national security of the US such as Chinese and Vietnamese as well as many Native American languages such as Navajo and Cherokee. A better understanding of the linguistic properties of these languages is a meaningful first step in increasing the communication efficiency with speakers of these languages and the development of better learning materials for these languages for native speakers of English. This project investigates the linguistic patterns of tone in two Chinese languages--Mandarin and Taiwanese--using state-of-the-art neurolinguistic techniques to shed light on how words with tones are represented in the speakers' brains. It contributes methodological innovations that will allow the different stages of the production processing of tone to be tracked by neurological measures. Moreover, this project involves international collaboration between a US institution and two prominent neurolinguistic laboratories in Hong Kong and Taiwan. The established connections will provide educational opportunities for students both in the US and internationally. This project focuses on tonal alternation patterns whereby a tone takes different phonological forms in different contexts, also known as "tone sandhi." Behavioral studies have shown that tone sandhi patterns extend to novel words in different ways, i.e., have different productivity, depending on the phonological nature of the pattern. This suggests that different mechanisms may be involved in the processing of this type of phonological alternation. This project uses event-related potentials (ERPs) to examine the time-course of the encoding of a number of tone sandhi patterns in Mandarin and Taiwanese in speech production. It is hypothesized that unproductive sandhi patterns are primarily subserved by a lexical mechanism that engages neural activities in an earlier time window of lexical retrieval (approximately 150-225 ms after the initiation of production), while productive sandhi patterns are primarily subserved by a computation mechanism that engages neural activities in a later time-window of phonological encoding (400-600 ms). It is also hypothesized that the neural activities of the lexical mechanism are sensitive to lexical frequency, while those of the computation mechanism are less so. This project will be the first to investigate the neural activities underlying the putative computation vs. lexical mechanisms associated with productive and unproductive phonological alternations. The increased understanding of the neural encoding of phonological alternation will inform both the theoretical models of speech production and formal models of phonological competence. Findings of this project can also be linked to issues of morphological decompositionality such as regularity and semantic transparency to achieve a fuller understanding of the neural bases of linguistic productivity.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.