Toronto, Apr 4 (IANS): Bilingual children are faster at switching tasks than children who speak only one language, a study says.

However, the study also found that bilinguals are slower to acquire vocabulary than monolinguals because they must divide their time between two languages while the latter focus on only one.

Raluca Barac and Ellen Bialystok of York University, Toronto in Canada tested 104 children. They compared the test results of English-speaking monolinguals to those of Chinese-English bilinguals, French-English bilinguals and Spanish-English bilinguals.

Bilingual and monolingual children were asked to press a computer key as they viewed a series of images -- either of animals or of depictions of colours, the journal Child Development reported.

When the responses were limited to either of the two categories, the children responded at the same speed. But when the children were asked to switch, from animals to a colour, and press a different button for the new category, bilinguals were faster at making the change than were monolinguals, said a university statement.

Researchers often use this switching task to gauge a set of mental processes known as executive functioning, generally defined as the ability to pay attention, plan, organise and strategise.

"In the simplest terms, the switching task is an indicator of the ability to multi-task," said Peggy McCardle, chief of the Child Development and Behaviour Branch at the Eunice Kennedy Shriver National Institute of Child Health and Human Development, which provided funding for the study.

"Bilinguals have two sets of language rules in mind, and their brains apparently are wired to toggle back and forth between them depending on the circumstances," said McCardle.