Doctoral Dissertation Research: Investigating cognitive and communicative pressures on natural language lexicons

理解人类如何产生和理解语言是理解高级人类认知和更普遍的人类大脑的关键一步。此外，对人类语言的基础研究已经并将继续有助于构建计算自然语言处理系统，使人类能够自然地与计算机进行交互。世界上成千上万种语言的词汇--也就是说，存在于任何一种特定语言中的词汇集--为深入了解语言的产生和理解机制提供了特别丰富的资源。任何一种语言的词汇都经历了数千年的演变，有时会在一两代人的时间里发生巨大的变化，因为声音发生了变化，新词被发明或从其他语言中借用，旧词消失了。然而，所有语言的共同之处在于，它们都能使使用者成功地相互交流。因此，一种语言的词汇必然受到说话人的认知和交际需求的制约。因此，研究词汇的统计特性、词汇的演变方式以及单词形成的过程，是回答人类认知基本问题的一条有前途的途径。该研究小组以前的工作表明，词汇往往是为了有效的交流而结构化的，在此基础上，本研究将利用互联网上提供的大型跨语言数据集，包括维基百科和谷歌图书，以研究大量世界语言的词汇（~100）。具体来说，本分析将集中在如何集群或蔓延的话在语音空间，探索竞争的要求，包括容易发音和易于理解的序列，但也是语音彼此不同的话。这项工作的第二个主要组成部分是一系列人类参与的行为实验，这些实验在受控的实验室环境中使用较少的语言，探索单词如何随时间变化的机制。最后，一个计算模型将被用来整合的统计分析和行为实验的见解，以探索和预测如何进入和退出随着时间的推移词汇。这项研究计划不仅对更高层次的人类认知有影响，而且对任何需要涉及自然语言的人机交互的工程应用，以及任何需要建立一个认知上易于处理的通信系统，使人们能够有效地进行通信的应用都有影响。

Understanding how humans produce and comprehend language is a critical step in understanding high-level human cognition and the human brain more generally. Moreover, basic research into human language has been, and will continue to be, useful for building computational natural language processing systems that enable humans to interact naturally with computers. The lexicons of the world's thousands of languages--that is, the sets of words that exist in any given language--offer a particularly rich source of insight into the language production and comprehension mechanism. The words of any given language have undergone thousands of years of evolution, sometimes changing dramatically over one or two generations as sounds change, new words are invented or borrowed from other languages, and old words die. What all languages have in common, however, is that they enable their speakers to successfully communicate with one another. Therefore, a language's lexicon is necessarily constrained by the cognitive and communicative demands of speakers. Consequently, studying the statistical properties of lexicons, the ways that lexicons evolve, and the process by which words are formed is a promising avenue for answering fundamental questions about human cognition.Building on previous work by this research group showing that lexicons tend to be structured for efficient communication, this research will harness the power of large cross-linguistic data sets available through the Internet, including Wikipedia and Google Books, in order to study the lexicons of a large number of world languages (~100). Specifically, this analysis will focus on how words cluster or spread out in phonetic space, exploring competing demands for words to consist of easy-to-pronounce and easy-to-comprehend sequences but also to be phonetically distinct from one another. A second major component of this work is a series of human-participant behavioral experiments that, in a controlled laboratory setting and in a smaller number of languages, explore the mechanisms that underlie how words change over time. Finally, a computational model will be used to integrate the insights of the statistical analyses and behavioral experiments in order to explore and predict how words enter and exit the lexicon over time. This research program has implications not just for higher-level human cognition but for any engineering applications that require human-computer interaction involving natural language and also for any applications that require building a cognitively tractable communication system that allows people to communicate efficiently.