FRIDAY, April 6 (HealthDay News) -- Children who grow up learning to speak two languages are better at multi-tasking than children who learn only one language, a new study finds.

But, the bilingual kids are slower to build their vocabulary.

The study of 104 children, age 6, compared those who spoke only English with those who were bilingual and spoke either Chinese and English, French and English, or Spanish and English.

The children were asked to press a computer key when they saw a series of computer images of either animals or depictions of colors. When their responses were limited to only one of the categories, all the children responded at the same speed.

However, when the children had to switch between categories and press different buttons for each category, the bilingual children were faster at making the change than the English-only children.

The U.S. National Institutes of Child Health and Human Development-funded study was conducted by researchers at the University of York in Toronto and appeared in the journal Child Development.

"In simplest terms, the switching task is an indicator of the ability to multi-task," Peggy McCardle, chief of the Child Development and Behavior Branch at the NICHD, said in a National Institutes of Health news release.

"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," she explained.

The English-only speaking children had the highest scores on tests of English vocabulary and English grammar and word meaning. This is because they are able to focus on one language, while bilingual children have to divide their time learning two languages, the researchers said.

More information

The National Center for Infants, Toddlers and Families has more about children's development of thinking skills.