The speed with which very young children learn languages fades very quickly if not used, according to a new research.

Researchers at the University of Washington's Institute for Learning & Brain Sciences wanted to see if they could improve bilingualism in adults by learning how babies do it and publish their research in the Journal of Phonetics.

Babies are naturally attuned to learning languages, but they quickly shut out sounds they don't need to concentrate on their mother tongue. But bilingual babies have a more open mind for longer the study found.

"But almost nothing is known about how bilingual babies do this for two languages. Knowing how experience sculpts the brain will tell us something that goes way beyond language development," said Patricia Kuhl, co-author of the study and co-director of the UW's Institute for Learning & Brain Sciences.

The study wired up babies from single language households and bilingual youngsters to electrode-studded caps connected to an EEG to measure brain activity.

The two languages were English and Spanish and the babies were played recordings of sounds from these languages.

The study found that at 6-9 months of age monolingual babies could detect both languages, but by the 10-12 months, this ability had disappeared.

Bilingual babies did not distinguish between the two languages at 6-9 months, but by the time they were 10-12 months old they could detect both.

Adrian Garcia-Sierra, lead author and a postdoctoral researcher at UW's Institute for Learning & Brain Sciences: "When the brain is exposed to two languages rather than only one, the most adaptive response is to stay open longer before showing the perceptual narrowing that monolingual infants typically show at the end of the first year of life."

Follow up research found that this early indicator of language ability stood the test of time, with the bilingual babies who showed the strongest responses to those early tests went on to have the largest vocabularies.

"Learning a second language is like learning a sport," said Garcia-Sierra, who is raising his two young children as bilingual. "The more you play the better you get."

Related Video: Patricia Kuhl: The linguistic genius of babies

Top Image Caption: One of the babies in the experiment wearing an EEG cap that measures brain activity. Credit: © University of Texas at San Antonio