Doctoral Dissertation Research: Late First Language Acquisition Effects on Phonological Processing in Sign Language

对于能够自动接触到周围使用的口语的听力人来说，迟习得第一语言的情况很少见，但这种情况在聋人中经常发生，他们听不到任何口语，而且直到儿童早期才接触到作为第一语言的手语。这些已故的第一语言聋人手语者会对生活的方方面面产生戏剧性的影响，包括语言效果。虽然之前关于这一主题的大部分研究都着眼于句子层面的语言结果，但这个项目旨在通过研究句子和单词层面下的签名者如何处理构成手势/单词的最小语言片段来更好地理解后期第一语言习得的影响。这项工作对于更全面地了解后期第一语言习得的影响，以及更好地洞察人类大脑如何更广泛地处理语言是必要的。实际上，这项工作帮助那些与聋人打交道的人，如言语语言病理学家和教育工作者，更好地理解第一语言签名者是如何处理构成语言的语言片段的。在本论文中，参与者是聋人手语者，他们在不同的年龄段获得了手语，从童年早期到青春期晚期。研究一通过手势重复和错误分析，考察手语使用者如何产生最小的手语片段(手形、动作和位置等手动形式)。研究二考察了手语使用者如何通过相似性判断来感知手语的手工形式。研究三考察了手语使用者如何通过手势监测和脑磁图识别和加工手语的手势。总而言之，这些研究洞察了较晚的第一语言签名者与较早的第一语言签名者相比是如何产生、感知和处理最小的手语片段的，从而系统地观察了较晚的第一语言习得在子词水平上的影响。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Late first language acquisition is rare for hearing individuals who have automatic access to spoken languages used around them, but it occurs frequently for deaf individuals who are unable to hear any spoken languages and who are not exposed to a sign language as a first language until after early childhood. These late first language deaf signers can experience dramatic effects on all aspects of life including language outcomes. While much of the previous research on this topic has looked at language outcomes at the sentence level, this project aims to better understand the effects of late first language acquisition by looking below the sentence and word levels at how signers process the smallest pieces of language that make up signs/words. This work is necessary for a more complete understanding of the effects of late first language acquisition and better insight into how the human brain processes language more broadly. Practically, this work helps those who work with deaf individuals, like speech language pathologists and educators, to better understand how late first language signers process the linguistic pieces that make up language. In this dissertation, participants are deaf signers who acquired a sign language at a variety of ages, from early in childhood to late in adolescence. Study 1 investigates how the signers produce the smallest pieces of the sign language (manual forms like handshape, movement, and location) through sign repetition and error analysis. Study 2 investigates how the signers perceive the manual forms of sign language through similarity judgments. Study 3 investigates how the signers identify and process the manual forms of sign language through form monitoring and using magnetoencephalography (MEG). Together, these studies provide insight into how late first language signers compared to early first language signers produce, perceive, and process the smallest pieces of sign language, providing a systematic look at the effects of late first language acquisition at the sub-word level.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.