Effects of bilingual language control on speaking - PROJECT SUMMARY/ABSTRACT Bilingualism brings fascinating cognitive and neural adaptations, thought to be brought about by the daily practice of language control, a set of mental processes ensuring the use of the appropriate language(s). The highest control demands are imposed by a dual-language context (speaking two languages in close succession but to different individuals; Adaptive Control Hypothesis, Abutalebi & Green, 2013). To understand language control and bilingual adaptations, it is key to understand how language control unfolds during naturalistic language production and how it interacts with the speaking process. However, this is currently unknown – existing evidence comes from constrained lab tasks, mostly involving saying single words. The current study will address this gap by determining the effects of language control during naturalistic language production in a dual language context. Spanish-English bilinguals dominant in English will describe the content of lab-created short videos. In a Two-language session, they will speak Language A before and after Language B. In a Single-language session, they will speak only Language A, before and after a distractor task. In Experiments 1 and 3, Language A will be the non-dominant language, and in Experiments 2 and 4, Language A will be the dominant language. The proposed research will determine the effects and added cognitive load of bilingual language control on speaking quality and fluency, to test predictions of language control theories. (1) Experiments 1-2 will establish the effects of language control on predetermined speech characteristics. Both theory and evidence predict slower speech rate, more pauses, fewer words, fewer unique words and higher-frequency words during both application and recovery from inhibition. A novel hypothesis is tested that adverse effects on some of these characteristics help others stay unaffected. (2) Experiments 3-4 will establish the added cognitive load of language control by measuring the rates of concurrent tapping of a trained sequence by one group of bilinguals. Slower tapping will index more effort. Language control theories predict that the application of inhibition is cognitively effortful. (3) The time- course of language control will be examined by analyzing changes of tapping rates across time, to further constrain language control theories. The proposed research will determine the effects of bilingual production dynamics on naturalistic language production, and will increase understanding of human cognition. It has major clinical implications. It will help determine criteria to distinguish healthy from impaired speech, establish potentially more cognitively effortful contexts of language use, and inform research aimed at understanding impaired bilingual speech. Analyses of speech characteristics could aid early diagnosis of incurable neurodegenerative diseases such as Alzheimer's disease (Ostrand & Gunstad, 2020). Implementation of the proposed research will also prepare underserved students for research careers.
