Doctoral Dissertation: Language Interaction in Child Bilingual Speech: an Acoustic Study of Diphthongs

在习得第一语言的过程中，儿童会发展出一套该语言特有的音素。同时学习两种语言需要掌握两套音素。双语儿童是将这两组音素彼此分开，还是在语言发展的任何阶段，两种语言的音素相互干扰？如果两个系统之间存在相互作用，这种相互作用的性质是什么？它与成年双语者的相互作用有何不同？为了解决这些问题，目前的项目研究如何双语儿童的两个语音系统的互动比较法英双语儿童年龄匹配的单语儿童的两种语言和成人法英双语。本研究的重点是双元音的习得，这是一种在文献中没有得到太多关注的复杂元音片段。以往关于单元音元音产生的研究表明，双语儿童的语言互动的影响，如重叠的语音特性，这是显着不同的单语者。本研究的结果将表明，是否以前建立的研究结果单元音元音的习得可以推广到双元音。此外，通过研究双元音的习得，该项目还解决了如何通过使用平滑样条方差分析来最好地捕捉复杂片段的动态特性的重要方法问题，这是一种比较元音产生差异的相对新颖的方法。这个项目将确定这种技术是否足以捕捉双元音的动态，以及它是否会产生比以前的技术更精确的结果。目前项目的结果将与双语儿童的父母以及与双语儿童合作的各种协会有关，这些协会可能对儿童双语习得的进展感到好奇。这些结果也可能与临床应用有关，如语音语言病理学。鉴于双元音语音的复杂性，本研究可能会发现，他们通常比单元音元音更难习得。因此，儿童可能表现出涉及双元音产生的言语延迟。目前的研究结果可能会成为有用的临床医生建设的基线数据有关的生产双元音。语言治疗师可以参考这个基线，特别是当试图区分真实的临床语言问题和双语的潜在副产品时，这可能被解释为语言障碍。

In the course of acquiring their first language, children develop a set of phonemes specific to that language. Learning two languages simultaneously requires the acquisition of two sets of phonemes. Do bilingual children keep these two sets of phonemes separate from each other, or do the phonemes of the two languages interfere with one another during any stages of language development? If there is interaction between the two systems, what is the nature of that interaction and how does it differ from that found in adult bilinguals? To address these questions, the current project examines how the two phonetic systems of bilingual children interact by comparing French-English bilingual children to age-matched monolingual children of both languages and adult French-English bilinguals. The study focuses on the acquisition of diphthongs, which are complex vowel segments that have not received much attention in the literature. Previous studies on the production of monophthong vowels have shown effects of language interaction in bilingual children, as evidenced by overlapping phonetic properties, which were significantly different from what was found for monolingual speakers. The results of this study will indicate whether the previously established findings on the acquisition of monophthong vowels can be generalized to that of the diphthongs. Additionally, by examining the acquisition of diphthongs, this project also addresses significant methodological issues on how to best capture the dynamic properties of complex segments by using the Smoothing Spline ANOVA, which is a relatively novel method for comparing differences in vowel production. This project will determine whether or not this technique is adequate for capturing diphthongs' dynamicity and whether or not it will produce more precise results than previous techniques. The results of the current project will be relevant to parents of bilingual children, and to various associations working with bilingual children that may be curious about the progression of children's dual language acquisition. The results may also be relevant to clinical applications such as speech-language pathology. Given the phonetic complexity of diphthongs, the current study may reveal that they are generally more difficult to acquire than monophthong vowels. Thus, children may show speech delays involving the production of diphthongs. The results of the current study may become useful to clinicians for the construction of baseline data regarding the production of diphthongs. Speech therapists may then refer to this baseline, particularly when trying to differentiate between real clinical speech problems and potential byproducts of bilingualism, which may otherwise be interpreted as speech impairment.