Doctoral Dissertation Research Improvement Grant: Structure and Plasticity of Bilingual Sound Systems

在日益全球化和移民的时代，每天听到的讲话变得越来越不同质，随着来自不同语言背景的人们之间的互动增加，各种口音和方言渗透到日常活动中。不同语言的说话者使用不同的声学信息来决定他们听到的声音。例如，虽然英语和西班牙语都有“p”和“B”之间的声音对比，但听众会注意声音信号的不同方面（或不同的“声学线索”），以确定两种语言中这些声音之间的差异。这意味着一个人在听另一种语言或外国口音的讲话时，可能没有注意到与说话者相关的声音的相同部分，这可能导致清晰度方面的困难。为了有效的言语理解，听众必须通过将注意力转移到与说话者相关的声音方面来迅速适应不同的口音。本论文的研究将探讨母语如何影响语音类别的产生和感知，以及当这些类别发生变化时，听者会在多大程度上适应。第一部分研究将探讨哪些声学线索与区分英语和西班牙语中的“p”与“B”等对比最相关。第二组实验将探索这些声音类别的“边界”如何被转移。也许最引人注目的适应性例子是双语者，他们毫不费力地立即从一种语言的声音转换到另一种语言。然而，单语听众也会改变他们的声音类别边界，以适应新的口音。拟议的研究将探索声音类别的可塑性，或者当听众面对与平常不同的发音时，他们改变类别边界的速度和幅度，就像听到不熟悉的外国口音时一样。这项研究还将调查双语者是否比单语者表现出更大的可塑性。总之，所提出的实验的结果将增加对声音类别在不同语言中的结构以及哪些因素有助于这些类别的可塑性的理解，更广泛的目的是深入了解理解外国或外国口音语音所面临的挑战。

In an era of increasing globalization and immigration, the speech heard on a daily basis is becoming less homogenous, and various accents and dialects permeate everyday activities as interactions between people from different language backgrounds increase. Speakers of different languages use different acoustic information to decide what sounds they are hearing. For example, while both English and Spanish have a sound contrast between "p" and "b," listeners pay attention to different aspects of the sound signal (or different "acoustic cues") to determine the difference between these sounds in the two languages. This means that a person listening to another language, or to foreign-accented speech, may not be paying attention to the same parts of the sound that are relevant for the speaker, which could lead to difficulties in intelligibility. For effective speech comprehension, listeners must rapidly accommodate to different accents by shifting their attention to the aspects of the sounds that are relevant for the speaker. The proposed dissertation research explores how one's native language can shape the way sound categories are produced and perceived, as well as to what extent listeners adapt when confronted with changes in these categories.The first part of the research will explore which acoustic cues are most relevant to distinguishing contrasts like "p" vs. "b" in English and Spanish. The second set of experiments will explore how the "boundaries" of these sound categories can be shifted. Perhaps the most striking example of accommodation is provided by bilinguals, who switch from using the sounds of one language to another effortlessly and instantaneously. However, monolingual listeners also shift their sound category boundaries to accommodate to new accents. The proposed research will explore the plasticity of sound categories, or the rate and magnitude at which listeners shift their category boundaries when confronted with speech that is pronounced differently than usual, as happens when hearing an unfamiliar foreign accent. The research will also investigate whether bilinguals show more plasticity than monolinguals. Together, the results of the proposed experiments will increase understanding of how sound categories are structured in different languages and which factors contribute to the plasticity of these categories, with the broader aim of providing insight into the challenges involved in understanding foreign or foreign-accented speech.