How do two languages exist in the same brain? Why is it possible for the brain to forget a language? How does bilingualism sculpt the brain? Over half of the world's population is bilingual and yet this fascinating, complex ability of the human brain is understood by few. In 'The Bilingual Brain', leading expert Albert Costa explores the science of language through a wide range of cutting-edge studies and examples from South Korea to Spain to Canada. Looking at the development of the brain from infancy to old age, Costa shows us the impact of bilingualism on everyday life: from a bilingual's ability to multitask and make decisions to the way in which they interact with those around them.