It is well known that someone who had been raised in Japan and whose mother tongue is Japanese can not tell the sound r from the sound l. If such a person were to hear the sentences He likes to read and He likes to lead taken out of context, he would most likely not be able to tell them apart. To him, both sentences would sound the same, because in his early youth his brain was adapted to the use of the Japanese language in which there is no difference between the two sounds. Similar peculiarities in perceiving the differences between sounds also occur in other language environments. The Spanish and the French distinguish the sounds b and p in a different way than the English. What sounds as a b to a Spanish person, would sound as a p to an English person. In contrast, a Thai person would distinguish three different variations within the sounds that we perceive only as b and p.
The structure of potential variations or phonemes that an individual can tell apart within the range of all possible sounds is stored in the brain very early in life, and can not be changed with learning later on. Once an individual acquires a language, he is forever condemned to distinguishing only between the sounds that exist as variations within his language environment.
Suckling on consonants
We all know little children can easily learn the language of the environment in which they are being raised, while later one has to try much harder to learn a new and unfamiliar language. Why is there such a difference? Would it be possible to activate the ability of spontaneous language acquisition later in life? Questions about how the brain learns to understand and produce a language have always fascinated scientists who have been involved in the active research of this field of science.
Because it is impossible to ask babies whether they can tell the difference between, for example, read and lead, scientist have come up with all kinds of alternative methods to test infants whether they can differentiate between individual sounds and find out when they start to lose this ability. They created an imitation of a breast which does not produce milk while the baby suckled on it, but sounds. The more the babies sucked the more distinct sounds were being produced, and the children were almost as pleased by this as if they were actually getting milk.
However, if the children could only draw a single, repeating sound out of the speakers, they would eventually grow tired of the activity. When the sound would change, though, they would start sucking more actively again. It was this very change in the intensity of sucking which revealed that children could tell the difference between two sounds, otherwise such a reaction would not have occurred at all. This made it possible to observe whether little children could differentiate between the sounds r and l, despite the fact that they were being raised in the Japanese language environment.
At first, scientists assumed that the children would not be able to detect the subtle differences between individual sounds, but that they would gradually learn to do so while they grew up. Surprisingly, they discovered that in fact the truth was just the opposite. Even month-old babies from the English language environment were able to distinguish between all the phonemes that were characteristic of the English language. These babies had already developed a framework of the English language within which they could tell the difference between all the different r sounds and all the different l sounds, but they could not detect the differences within both individual groups of sounds, even though they were pronounced by different speakers.
The surprises kept on coming. When they tested babies from other language environments, they found out, for example, that also Mexican children of the Spanish language environment could easily distinguish between the different sounds of the English language. Similarly, Japanese babies had no difficulties with telling apart the sound r from the sound l, despite the fact that their parents were unable to do so themselves.
Babies can speak all languages?
Infants can distinguish between phonemes of all the existing languages of the world even when they had never heard a certain language before. It makes no difference whether the sounds are French, English, Chinese or Slovenian, infants have no difficulties with telling them apart regardless of who pronounces them, be it a man, a woman or a child. Babies have an inherent aptitude for learning languages. In fact, they have a sort of universal talent for learning any of the approximately 6000 languages that still exist today.
It is also important to emphasize that a child does not merely distinguish individual sounds like a computer detector which can be set to detect the difference in the frequency of two consecutive sounds. Children are able to correctly categorize sounds by classifying them into groups on the basis of which words are formed. When born, every child functions like a sort of universal receiver that can acquire any language. The key question that arises is why babies, which are born as universal linguists, later become specialized in their language only, and lose the ability to differentiate between the phonemes of other language environments.
Because the breast imitation test was not as effective with older infants, scientists have developed other methods to monitor their responses to different sounds after they have reached six months of age. Today, electric sensors are used for this purpose, attached to the child’s head with a sort of hat that measures minute differences in brain activity, and can detect when the child notices or fails to notice a difference between two phonemes.
In Japanese children, researchers discovered that they could easily distinguish between the English r and l at the age of seven months, but would lose this ability only three months later. Nine-month-old Japanese children could no longer tell the difference between the two sounds while American children of the same age actually became more susceptible to this difference. A similar research conducted on Canadian children revealed that at six months of age they were capable of distinguishing between phonemes of exotic languages which their parents and their twelve-month peers could no longer tell apart. After their first birthday, a child’s brain no longer has the universal flexibility to acquire any language, but has already been adapted, so it can absorb the language of its environment more easily.
With different research methods, scientists have learned that the loss of the universal ability to differentiate between phonemes also occurred on a comparable level in deaf children when they were being communicated with in sign language. All children starting to learn a language lose their universal ability at this age, but become much more specialized in distinguishing between the phonemes of their language.
Research has shown that children, once they have lost their universal ability to differentiate between phonemes, begin to learn the language of their environment more rapidly than their peers who remain sensitive to the sounds of more exotic languages for a longer period of time. This is so because communication is substantially easier when the brain only focuses on the differences important for conveying information and ignores everything else.
The time when children start losing the ability to tell apart the sounds of exotic languages approximately coincides with the time when they redirect their attention from sounds to words. That is when they start to get familiar with all the possible words in their language environment. Researchers have found out that nine-month-old children prefer listening to sets of sounds that correspond to the rules according to which sounds are usually combined in their language, even if they do not actually exist in the vocabulary of their language environment.
Direct contact is important
Also fascinating is the latest research that underlines the importance of direct personal interaction with the child learning a language. Scientists wanted to find out whether exposing children to an exotic language could prolong their universal ability to differentiate between phonemes.
Nine-month-olds were separated into four groups. For a couple of weeks, the children in the first group would occasionally play with Chinese teachers, who communicated with them solely in Chinese, even though the children had been raised in a strictly English speaking environment. The second group of children watched the Chinese teachers on video, the third group only listened to them and the fourth group had no contact with them at all.
What was interesting about the results of this experiment was that only the children who had been in direct contact with the teacher who communicated with them in Chinese preserved their ability to tell apart exotic phonemes later on. Their peers in the control groups, who had only listened to Chinese or watched the teachers on video, lost their ability to distinguish between phonemes just like the children who had no contact with Chinese at all.
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