Doctoral Dissertation Research: Why adapt? Phonotactic learning as non-native language adaptation

为了成功地交流，听者必须不断适应说话者之间的系统差异（例如，根据说话者的方言改变你对将要听到的内容的期望）。与此同时，听众需要忽略偶然的变化（例如，如果一个说话者碰巧嘴里塞满了东西，你不应该改变你对他们吃完后说话方式的预期；Kraljic, Brennan, & Samuel, 2008）。在这项研究中，一系列的实验检验了适应新语音策略的局限性，或者对音节结构的限制（例如，在英语中，而不是西班牙语中，顺序/sk/可以作为音节的开头，例如在单词school中）。这个项目测试了这样一个假设，即说话者使用他们过去的音形变化经验来区分系统变化和偶然变化。说话者在不同语言的说话者之间自然会遇到语音策略的变化，但在同一语言的说话者之间不会遇到这种变化；该理论预测，说话者只有在接触语言背景不同的说话者（例如，母语为法语的人和母语为英语的人）时，才会适应特定于说话者的音节结构。这一假设在三个实验中得到了验证。在研究1中，在感知实验中，听众被暴露在两个说话者面前，每个人都有不同的语音定向限制。只有当说话者的语言背景不同时，才能预测对说话者特定约束的适应。研究2以绕口令为例，探讨了说话者语言背景对语音策略适应的影响。研究3考察了听者先验知识的结构和粒度。侦听器是否可以只持有母语与非母语的模型，还是可以维护两种独立的非母语的模型？

In order to successfully communicate, listeners must continuously adapt to systematic differences between speakers (e.g., changing expectations about what you will hear based on a speaker's dialect). At the same time, listeners need to ignore incidental variation (e.g., if a speaker happens to be talking with their mouth full, you should not change how you expect they will speak after they have finished eating; Kraljic, Brennan, & Samuel, 2008). In this study, a series of experiments examine the limits of adaptation to novel phonotactics, or constraints on syllable structure (e.g. in English, but not Spanish, the sequence /sk/ can begin syllables, such as in the word school). This project tests the hypothesis that speakers use their past experience of phonotactic variation to distinguish systematic from incidental variation. Speakers naturally encounter variation in phonotactics between talkers of different languages, but do not encounter such variation between talkers of the same language; this predicts that speakers will only adapt to talker-specific syllable structures when exposed to talkers who differ in their language backgrounds (e.g., a native French talker and a native English talker). This hypothesis is explored in three experiments. In study 1, listeners are exposed to two talkers, each with a different phonotactic constraint, in a perception experiment. Adaptation to talker-specific constraints is predicted only when talkers differ in language background. Study 2 explores the role of talker language background on adaptation to phonotactics in speech production, using a tongue twister paradigm. Study 3 investigates the structure and granularity of listeners' prior knowledge. Can listeners hold models of only a native vs. non-native language, or can they maintain models for two separate non-native languages?