Nearly half the world's people are bilingual, but many have no clear understanding of what - aside from being fluent in more than one language - bilingualism means. This lively introduction by linguist Penelope Gardner-Chloros covers everything a bilingual (or curious monolingual) individual might want to know. The book discusses how bilingualism affects brain development and performance in the young and old, its social and political significance throughout time and around the globe, and how people experience and describe it.