How flexible are grammars past puberty? Evidence from Turkish-American returnees

Can a language whose development was delayed and interrupted in childhood due to insufficient input be fully developed in adulthood with full immersion in the language? This dissertation investigates the flexibility of linguistic competence past puberty of a language acquired incompletely in childhood, with full immersion in the language in adulthood. Research has shown that heritage speakers show structural differences in the domains of inflectional morphology and morphosyntax due to reduced heritage language input in childhood or transfer from the majority language (Montrul & Polinsky, 2021). Intervention studies with explicit grammatical instruction have shown that heritage speakers can recover aspects of a childhood language in adulthood (Montrul & Bowles 2010, Muāgututiʻa, 2018), supporting the Permanence Hypothesis (Brenner, 2010, as cited in Muāgututiʻa, 2018; see also Bowers et al., 2009), which states that linguistic knowledge acquired during the critical period, underused or underdeveloped throughout childhood, remains available when reactivated in adulthood. This study takes this line of research a step further and asks whether interrupted acquisition before puberty in an immigration context can result in full nativelike attainment if heritage speakers are tested in a naturalistic setting, when fully immersed in and using the heritage language, in a majority language context (i.e., in the homeland). To this end, Turkish American returnees with varying age of return to Turkey (including those who returned to Turkey before and after puberty) are compared to Turkish heritage speakers residing in the United States as well as Turkish-speaking adults in Turkey (i.e., the baseline group). Three broad research questions are asked: 1) To what extent do Turkish-American returnees show convergence towards target-like competence of Turkish morphology and complex morphosyntax upon full immersion in Turkish after their return?, 2) Which areas of grammar can be robustly acquired with maximal input, and which ones may be subject to maturational effects past puberty?, and 3) To what extent do situational factors such as the sociopolitical status of the former dominant language and the socio-economic status of the heritage speakers play a role in heritage language development in returnees? To answer these questions, five vulnerable structures (Differential Object Marking, evidentiality, relative clauses, anaphoric reference and verbal passives) in Turkish heritage speakers are examined (Coşkun Kunduz & Montrul, 2022a, b). Four offline tasks were used to test these: a context-based Acceptability Judgement Task, a Sentence Repetition Task, a picture description task and a story-telling task. The results have revealed that regardless of their age of return to Turkey or length or residence in Turkey after their return, the Turkish-American returnees reached target-like competence of complex morphosyntax, including verbal passives, relative clauses and anaphoric dependencies, in Turkish. Although they still preserved features typical for heritage speakers in the domain of inflectional morphology (DOM and evidentiality) many years after returning to their home country, overall the returnees showed reactivation and convergence towards target-like competence in this domain as well. Crucially, however, age of onset of bilingualism, the role of English as a lingua franca and the degree of contact with English upon their return did not play an important role in the returnees’ performance. Taken together, these findings are in line with the prediction of the Permanence Hypothesis and suggest that grammars are still and malleable after puberty.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Linguistics

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2024

Author dc:creator

• Coskun Kunduz, Aylin

Contributors dc:contributor

• Montrul, Silvina
• Ionin, Tania Ruth
• MacDonald, Jonathan
• Flores, Cristina

• Bilingualism
• Heritage Language Acquisition
• Turkish
• Returnees
• Turkish-american
• Inflectional Morphology
• Morphosyntax

Statement dc:rights

• Copyright 2024 Aylin Coskun Kunduz

Language dc:language

en, eng

Handle dc:identifier

https://hdl.handle.net/2142/127320

OAI record oai:identifier

https://www.ideals.illinois.edu/oai-pmh?verb=GetRecord&metadataPrefix=etdms&identifier=oai%3Awww.ideals.illinois.edu%3A2142%2F127320