Few areas of linguistics are surrounded by as many misconceptions as is bilingualism. Most people think that bilingualism is a rare phenomenon found only in such countries as Canada, Switzerland and Belgium and that bilinguals have equal speaking and writing fluency in their languages, have accentless speech and can interpret and translate without any prior training. The reality is in fact quite different: bilingualism is present in practically every country of the world, in all classes of society and in all age groups; in fact, it has been estimated that half the world's population is bilingual. As for bilinguals themselves, the majority acquired their languages at various times during their lives and are rarely equally fluent in them; many speak one of their languages less well than the other (and often with an accent) and many can only read or write one of the languages they speak. Furthermore, few bilinguals are proficient interpreters and translators.
In this entry we will describe the many facets of the bilingual individual. We will concentrate on the adult and will focus on the stable bilingual, that is the person who is no longer in the process of acquiring a second or third language. We will first describe the bilingual person in terms of language knowledge and use. We will then examine the bilingual's linguistic behavior when communicating with monolinguals and with other bilinguals. We will continue by discussing a certain number of issues in the psycholinguistics and neurolinguistics of bilingualism, and we will end with a brief overview of the attitudes, behaviors and personality of the bilingual individual.