Language is full of ambiguities, ranging from challenging phonetic contrasts to homophones and homographs. While some ambiguity is inherent in any language, the challenge of resolving linguistic conflicts is even greater for those who speak multiple languages. The question of how bilinguals represent and control their two languages has been addressed using various methodologies ranging from case studies of multilingual aphasics to advanced neuroimaging techniques. In this chapter, we focus on two methods in particular that have contributed to the understanding of bilingual cognition. First, we review evidence from eye-tracking studies demonstrating that bilinguals activate their two languages in parallel. We follow with a discussion of fMRI research investigating whether different languages have shared or separate representations in the brain. Finally, we examine the processes underlying language control and discuss the ways in which different methodologies can contribute to our understanding of bilingual language processing.

This chapter elucidates the behavioral and neural underpinnings of bilingual lexical ambiguity processing during both first language (L1) and second language (L2) reading. It provides an overview of the eye-tracking and functional magnetic resonance imaging (fMRI) research on bilingual nonselective lexical access, as assessed through cognates, interlingual homographs, and cross-language orthographic neighbors (i.e., words that are lexically ambiguous across languages). Ultimately, the chapter demonstrates that eye movement patterns vary as a function of the nature and amount of cross-language overlap, as well as individual differences in L2 background and executive control capacity. It also demonstrates that left hemisphere brain regions implicated in executive functions (e.g., inferior frontal gyrus, dorsolateral prefrontal cortex, basal ganglia) are also implicated in resolving cross-language lexical ambiguity.

This chapter provides an overview of research conducted over the past few decades on bilingual lexical access during reading using eye movement measures. We first present a summary of earlier work on bilingual single-word processing and outline the predictions of the bilingual interactive activation plus model (BIA+; Dijkstra & Van Heuven, 2002) regarding bilingual lexical access during reading. We then review the studies focusing on lexical access during L2 processing and then during L1 processing, while distinguishing systematically early and late stages of processing. Overall, the findings demonstrate that bilingual lexical access during reading is nonselective, as predicted by the BIA+, and that cross-language activation may occur more strongly during L2 than during L1 reading. Several other factors, such as semantic constraint and L2 proficiency, are also identified that modulate cross-language activation and the unfolding of lexical access.