Bilingualism

Bilingualism

Consequences for Language, Cognition, Development, and the Brain

Bilingualism

Every year, thousands of middle- and upper-class American children study a foreign language for enrichment. These children, their parents, and their teachers are guided by the belief that knowing another language "is good for you." At the same time (and sometimes in the same schools) thousands of other children—usually from immigrant and lower-class backgrounds—are discouraged from and sometimes forbidden to speak their native language. Their families are told that communication in their native languages will prevent them from mastering English and that raising children with more than one language will "confuse" them and have long-lasting, detrimental effects.

Given these two contradictory perspectives, what does research say about the consequences of bilingualism?

What Clinicians Should Know

Knowledge of bilingualism suggests the following linguistic, cognitive, and neurophysiological differences between bilingual and monolingual speakers:

Linguistic differences

• Bilingual children develop an earlier understanding of taxonomic relationships than their monolingual peers (e.g., car and bus are vehicles). This understanding is not dependent on vocabulary size, but could be influenced by the structural features of the speaker's language.
• Bilingual adults are better than monolingual adults at learning new words. Bilinguals use a variety of word-learning strategies with similar efficiency and are less susceptible to interference from conflicting orthographic information during word-learning.
• Linguistic input co-activates both languages in bilinguals; when bilinguals hear or read words in one language, partially overlapping linguistic structures in the other language also are activated.

Cognitive differences

• Bilinguals may be able to inhibit irrelevant verbal and nonverbal information with greater ease than monolinguals. Inhibitory control ability is slower to decline with age in bilinguals than in monolinguals.
• The average age of dementia onset is later in bilinguals than in monolinguals.
• Bilingual children have been found to exhibit superior performance in divergent thinking, figure-ground discrimination, and other related meta-cognitive skills.

Neural differences

• Bilateral processing of language (and other nonverbal tasks) is most likely to occur only in early bilinguals.
• Monolinguals and bilinguals use similar neural regions for language processing. However, late bilinguals are likely to activate the LIFG differentially for processes in which the LIFG plays a crucial role, such as phonological and syntactic processing.
• Bilinguals have greater gray matter density than monolinguals in certain left hemisphere regions.

(source: http://www.asha.org/publications/leader/2009/091013/f091013a.htm)