The Advantages of Bilingualism Debate

Bilingualism was once thought to result in cognitive disadvantages, but research in recent decades has demonstrated that experience with two (or more) languages confers a bilingual advantage in executive functions and may delay the incidence of Alzheimer's disease. However, conflicting evidence has emerged leading to questions concerning the robustness of the bilingual advantage for both executive functions and dementia incidence. Some investigators have failed to find evidence of a bilingual advantage; others have suggested that bilingual advantages may be entirely spurious, while proponents of the advantage case have continued to defend it. A heated debate has ensued, and the field has now reached an impasse. This review critically examines evidence for and against the bilingual advantage in executive functions, cognitive aging, and brain plasticity, before outlining how future research could shed light on this debate and advance knowledge of how experience with multiple languages affects cognition and the brain.