Some scientists believe that speaking a second language could confer lasting cognitive advantages in aging and stave off the onset of dementia (Bialystok et al., 2007; Craik et al., 2010; Abutalebi & Rietbergen, 2014; Grant et al., 2014; Woumans et al., 2015; Klein et al., 2016; Abutalebi & Green, 2016; Smirnov et al., 2019). However, this exciting claim has suffered significant setbacks over recent years due to a replicability crisis and a barrage of criticisms (Hilchey & Klein, 2011; Paap & Sawi, 2014; Paap et al., 2015). Proponents of the bilingual advantage hypothesis argue that the overhead of managing multiple languages is a demanding endeavour that rewires the brain over time. Critics, on the other hand, argue that this claim is exaggerated or unfounded. They contend that there is no evidence showing that bilingualism is more demanding than speaking a single language. Recent evidence emphasizes the need for a better understanding of bilingual language use in natural contexts in order to resolve this debate, but, until recently, it has been difficult to study the language processing in the brain in a naturalistic context. Over the course of three studies, I use simultaneous eye-tracking and functional magnetic resonance imaging (fMRI) to investigate the functional consequences of bilingualism in the brain during a naturalistic reading task. Data collected from three different subject pools, English speaking monolinguals, Chinese-English bilinguals living in the USA, and Chinese-English bilinguals living in China are used to evaluate the ecological validity of the claims made by the Adaptive Control Hypothesis (Green & Abutalebi, 2013) regarding the role that different bilingual contexts play in adaptive to changes to neural function. In addition, I also test a novel hypothesis which posits that bilingualism has ubiquitous consequences for the control of memory (Cunnings, 2017a; Cunnings, 2017b), a possible missing link in the chain of reasoning which connects the management of multiple languages to improved cognitive aging. The results provide timely evidence that bilingualism indeed has behavioral and neural consequences for the control of their two languages during an uncontrolled reading task and contributes multiple, convergent findings suggesting that these consequences may affect memory. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]