|Bilingual baby wearing a cap studded with electrodes|
American researchers have been investigating the brain mechanisms that make babies such a whizz at learning languages in the hope of finding a way to boost adult language learning skills.
We have written before on these pages about how babies are born with the ability to make any language sound, from the Welsh ‘ll’ to the French ‘r’ to the Russian myagki znak (soft sign). But the brain, being a highly efficient tool, gradually closes down the ability to make sounds that are never used.
Thus, at around 8-10 months, monolingual babies become increasingly capable of detecting the sounds of their native language while gradually losing the ability to distinguish sounds from foreign languages. For example, a baby in a monolingual English household will learn to detect the difference between ‘l’ and ‘r’ sounds which are prevalent in English while a monolingual Japanese baby, for example, will lose this ability as they will not be exposed to these two sounds.
This is why, when you learn languages later in life, you will only ever learn to mimic these sounds whereas the sounds, in other words languages, you learn as an infant come naturally.
Now, in a bid to find a way to boost bilingualism in adults, American scientists have conducted research into the brain activity of bi- and monolingual babies to show the theory in action and demonstrate how this period of flexibility lasts longer in bilingual babies than in monolinguals.
‘The infant brain tunes itself to the sounds of the language during this sensitive period (8-10 months) in development, and we're trying to figure out exactly how that happens,’ says Patricia Kuhl, co-director of the University of Washington’s Institute for Learning and Brain Sciences and co-author of the study.
Researchers at the UW Institue fitted caps with electrodes to the heads of babies growing up in monolingual (English) and bilingual (english/Spanish) homes to measure the flow of energy to the brain.
The babies then listened to background sounds in one language with a sound from the other language appearing occasionally. When the baby detects a sound from the second language, this ‘mismatch response’ can be detected by the EEG device.
At 6-9 months, monolingual babies showed the mismatch response for the second language whether it was English or Spanish, but by 10-12 months the only reacted to the English sounds.
In contrast, babies used to hearing the two languages showed no mismatch response at 6-9 months and at 10-12 months they continued to pick up the other language, be it Spanish or English.
This suggests that the bilingual brain, exposed to a greater variety of speech sounds, remains flexible to languages for a longer period of time whereas monolingual babies’ brains commit to one language towards the end of their first year.
The researchers then revisited the children at 15 months to see if their early brain responses were indicative of their later speaking skills and found that the bilingual babies’ vocabulary was indeed directly related to their ability to continue to discriminate between languages at 10-12 months, showing a direct link between brain activity in infancy, exposure to languages and speaking ability.
‘The bilingual brain is fascinating because it reflects humans' abilities for flexible thinking – bilingual babies learn that objects and events in the world have two names, and flexibly switch between these labels, giving the brain lots of good exercise,’ says Kuhl.