Doctoral Dissertation Research: How flexible are grammars past puberty? Evidence from heritage language returnees

这个博士论文项目解决了理解语言习得的一个基本问题：青春期后的语法有多灵活和可塑？语言习得文献中对年龄效应的讨论由来已久。一些人认为，如果在生命的后期（青春期之后）开始习得一门语言，以母语为母语的人是不可能达到的。传统语言习得的研究为这一争论提供了新的视角。传统语言使用者从出生起就在社区使用多数语言的环境中学习一门少数民族语言。由于在社会成长过程中广泛使用多数语言，传统语言使用者通常很少有机会与他们的少数民族（传统）语言互动，并且在传统语言中接受的语言输入总体上少于母国中典型发展的单语使用者。因此，在他们的传统语言的一些特性上，非母语的成就是很常见的。这被认为是早期习得是一个必要但不是充分的因素，因为早期接受的传统语言输入也起着作用。本研究探讨了年龄和输入因素在语言习得过程和最终成就中的相互作用。调查人员比较了两种不同移民背景下的传统发言者和在青春期或成年时期返回原籍国的海归。通过比较回归者使用原母语的语言能力与所在国使用传统语言的人的语言能力，可以得知，如果传统语言者在返回母国后完全沉浸在传统语言中，那么在青春期前习得中断是否会导致与母语相近的成就。我们还调查了环境因素（例如，与原多数语言的地位和接触、社会经济地位、教育背景）是否对海归传统语言的发展程度和速度起作用。为此，本研究获取了参与者的生产和语言判断数据。这个项目的结果有助于对少数民族语言的儿童和成人使用者的语言认同和语言自尊及其重新融入其母语和文化的有限文献作出贡献。研究结果还为传统语言教学的教学干预和为传统语言使用者设计教材提供了信息。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

This doctoral dissertation project addresses a fundamental issue at the heart of understanding language acquisition: how flexible and malleable are grammars after puberty? Age effects have long been discussed in the language acquisition literature. Some have argued that native speaker attainment of a language is impossible if acquisition starts later in life (after puberty). Research on heritage language acquisition provides a new perspective on this debate. Heritage speakers acquire a minority language at home from birth in a setting where the majority language is spoken in the community. Due to the extensive use of the majority language in the society growing up, heritage speakers often have fewer opportunities to interact with their minority (heritage) language and receive overall less linguistic input in the heritage language than a typically developing monolingual speaker in the home country. As a result, non-native-like attainment in several properties of their heritage language is common. This has been taken as evidence that early age of acquisition is a necessary but not a sufficient factor for native-like attainment because linguistic input received in the heritage language in early years plays a role as well. This study examines how age and input factors interact in language acquisition processes and in ultimate attainment.The investigators compare heritage speakers across two different immigrant contexts to returnees who have returned to their country of origin in their adolescence or adult years. Comparing the linguistic abilities of returnees in their former heritage language to that of heritage speakers in the host country informs whether interrupted acquisition before puberty can result in nativelike attainment if heritage speakers become fully immersed in the heritage language after returning to the home country. We also investigate whether the situational factors (e.g., status of and contact with the former majority language, socio-economic status, educational profile) play a role in the degree and speed of development of the heritage language in returnees. To this end, the study obtains production and linguistic judgment data from participants. The results of this project contributes to the limited literature on language identity and linguistic self-esteem in child and adult speakers of a minority language and their reinsertion in their native language and culture. The findings also inform pedagogical interventions in heritage language teaching and the design of teaching materials for heritage speakers.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.