Babies who hear foreign speech in their first 9 months of life retain the ability to recognise different sounds and find it easier to pick up languages in school or as adults, a study says.
Psychologists at Bristol University found that the developing brain undergoes a period of "programming" in infancy which sets up for life its ability to recognise key sounds in whatever will become its native language.
This process helps the brain make sense of speech by filtering out sounds not used in the native language, but also makes it harder to recognise unfamiliar sounds from foreign languages.
Crucially, babies exposed to multiple languages during their first few months retain the ability to recognise sounds from all the languages they hear.
English speakers, for example, usually only recognise one "k" sound, but Irish Gaelic, Russian and Turkish speakers can differentiate between hard and soft "k" sounds, which produce different meanings in those languages.
Similarly, English speakers often struggle to hear the difference between the French "u" sounds in "loup" and "lu" despite the words having quite different meanings – wolf and the past participle of read.
Dr Nina Kazanina, an expert in linguistic psychology at Bristol, said: "When a baby is born, it has the capacity to distinguish every type of speech sound. Even if the parents are English, the baby has the capacity to distinguish Greek and Chinese vowel sounds.
"By six months an infant can only recognise vowels from its native language, and within another two or three months the same happens to consonant sounds. So within around nine to 10 months, a baby's universal language ability is reduced to its native language.
"This happens because the brain is trying to make sense of sounds used in speech in the context of the native language, and so applies a kind of filter to help make it easier to understand words."
Dr Kazanina has been using techniques that measure the levels and location of electrical activity in the brain in response to different speech sounds. She found that while Gaelic speakers generated two separate states of activity when listening to hard and soft "k" and "g" sounds, English speakers only generated a single state of activity to both sounds, as they were unable to detect the subtle differences.
"While this is useful for the native language," said Dr Kazanina, "it can have a rather sad effect when it comes to learning foreign languages. Foreign sounds are often categorised using the native language filter and can lead to misperception."
She believes this explains why English speakers struggle to learn French compared with Italian and Spanish speakers, who have more similar sounds in their native tongues.
But the effect can work in the opposite direction too. English speakers find it far easier to pronounce Russian vowels than Russians do English vowels because English has more vowel sounds, so those who speak it have a broader repertoire.
In a similar way, Japanese and Chinese speakers are unable to tell the difference between "r" and "l", so get them confused when speaking English.
Dr Kazanina added: "Languages such as German and Swedish probably share most sounds with English, and so will be relatively easy to learn, but you must remember other characteristics like grammar and sentence structure."
A separate study at the University of Washington has shown that speaking different languages to babies in their early lives can be crucial in helping them learn new languages later in life. Researchers found that babies who were spoken to in Chinese for just one hour a week found it easier to recognise Chinese speech when they were older.
The Daily Telegraph
