Up until fairly recently, our knowledge of how our brains process language was fairly limited. Over the last few years, however, new developments in neuroscience investigations have enabled researchers to begin to piece together a much clearer picture of what happens in our heads when we speak, listen or read. And some fascinating results have already emerged. Now researchers are also looking into aspects of second-language processing and how different languages are handled by our brains. Although it is early days, and significant implications for language teachers are still a long way off, it is well worth taking a preview at the fascinating world of brain imaging.

Left and right

Little more than a decade ago, most of our knowledge of how our brains handle language was based on studies involving patients with brain damage. By studying people who had suffered strokes or other forms of impairment to parts of the brain, it was possible to pinpoint with some degree of accuracy which areas of the brain were involved with which functions.

It has long been known, for example, that the left-hand side of the brain is generally more involved in language functions. This is true for 97-98% of all right-handed people (who make up around 90% of the population). The situation is slightly different for the other 10% of the population, people who are left-handed or ambidextrous. Although most of this minority group also predominantly use the left hemisphere of their brains (around 67-68%), a good number use the right side to a greater extent (about 19%), while no significant pattern emerges for the remainder. Nevertheless, all left-handers tend to make a greater use of both hemispheres. Evidence also suggests that while left-handers are particularly good at maths and art, they may have greater difficulties with language, and dyslexia appears to be more common among left-handers (up until research on brain-damaged patients was published in the late 1970s, dyslexia was often put down to inattentiveness or even backwardness).

Deep in the left

For most people, therefore, the left hemisphere of the brain tends to dominate all language functions, and within the left side of the brain, we can identify certain specific areas that play a major role in handling language. Again, decades of observing patients with brain damage led researchers to discover that specific parts of the brain are associated with certain language functions. A good many of these areas are located well within the brain, away from the cortex, and they tend to be located around the Sylvian fissure, a deep fold inside the brain more or less parallel to a line running from the eye to the ear. Along the Sylvian fissure lie areas such as Broca's area, discovered by a French physician named Paul Broca, which is principally responsible for controlling the mechanical aspects of speech. Another area, known as the temporal lobe, includes areas that are responsible for hearing perception: Wernicke's area is believed to play a role in finding words and feeding them to other parts of the brain, while the angular gyrus (a gyrus being a "ridge" of the brain) assists in making some sense of the words and letters we come across… and we could go on identifying various language functions in various areas of the brain. What is particularly interesting is that most of these areas lying in the left hemisphere of the brain are closely linked to each other, as shown very simplistically by the darker grey areas in the following diagram.

Brain imaging techniques

In the last decade or so, new ways of investigating how the brain handles language have become available to researchers. Such techniques are known as brain imaging, or neuro-imaging, and make use of machines originally developed for medical purposes, such as the widely-known CT scanner. But while Computer Tomography (CT) scans have proved to be particularly helpful for medical purposes, they have not proved to be the most useful machines for seeing how the brain handles language since the scans only show the structure of the brain, not how it functions. A much more useful machine for linguistic purposes is the PET scanner, providing Positron Emission Tomography scans.

A PET scanner can detect a radioactive substance that has been injected into or inhaled by the subject. Once in the bloodstream, the material tends to accumulate in the areas of the brain that are most active. PET scans therefore indicate the areas of the brain that are activated during any particular mental task. Other brain imaging methods include Magnetic Resonance Imaging (MRI), which detects radio-frequency signals, and Functional Magnetic Resonance Imaging (fMRI) which detects blood flow in certain parts of the brain. When digitally processed, the results of such imaging techniques can provide fascinating pictures of the brain at work.

Research work being carried out

Various teams of researchers around the world are piecing together more and more information about how our brains work, and in particular how our brains work with language. Research is being carried out on dyslexia, even comparing the brain functions of dyslexic subjects whose mother-tongues differ. However, the research areas that are most likely to be of interest to MET readers relate to aspects such as how the brain functions during learning tasks, the way the brain handles a foreign language (compared with a native language) and the different areas of the brain required to carry out certain language tasks in different languages. All of these fields of research are already offering amazing insights to what happens inside our heads.

Listening and speaking in the mother-tongue

Research carried out at the Washington University School of Medicine in St. Louis, USA, has confirmed that when listening to a text, the most active areas of the brain are those in the temporal lobe (responsible for hearing perception) and the pre-frontal cortex (responsible for understanding language). On the other hand, when language is being produced, the main area of activity is Broca's area (responsible for motor control of the voice).

Brain activity with a foreign language

Various other experiments have concentrated on comparing how the brain handles the mother-tongue and a foreign language. Obviously the learning process is usually very different – the mother-tongue being learned as a young child in an effortless, spontaneous way, a foreign language generally being learned later in life and in a more structured fashion, often requiring a substantial amount of application. It is hardly surprising, therefore, to find that experimental work has shown that different areas of the brain are involved in dealing with the mother-tongue and the foreign language. Research carried out in France by the Laboratoire de Sciences Cognitives et Psycholinguistique, in co-operation with an Italian team led by Daniela Perani at the San Raffaele Hospital in Milan, has managed to detect the different areas.

The Italian experimenters examined the listening process in subjects whose mother-tongue was Italian, and whose knowledge of English was reasonably good, though they had not started learning it before the age of seven. The subjects were asked to listen carefully to three-minute texts in Italian, English and Japanese (an unknown language for them) as well as three minutes of silence broken by occasional sounds (for control purposes). While listening to an Italian text, the areas activated in the brain were those we would expect for the mother-tongue (mainly the left hemisphere, and in particular the upper and middle areas of the temporal lobe and the lower frontal gyrus). When listening to English, however, brain activity more or less disappeared in the temporal lobes, particularly in the lower temporal areas. And even more surprisingly, the picture was more or less the same when listening to a totally unknown language, Japanese. Throughout the group as a whole, listening to both English and Japanese created some slight extra activation in the middle (left) temporal area, but no other clear overall patterns emerged for brain activity.

In order to try to explain this apparent general lack of brain activity when listening to English, despite the fact that the subjects were familiar with the topic they were hearing, the hypothesis was put forward that different subjects were handling the foreign language in different ways. The French researchers therefore went on to examine the way that individual subjects coped with comprehension in English. While little variety was found in the way that the subjects handled listening tasks in their mother-tongue (this time French), there proved to be an astonishing variety in the way that English was being understood. Certain subjects were activating areas of the right hemisphere, corresponding more or less to the areas used in the left hemisphere for their mother-tongue. Others were using Broca's area (normally used for controlling speech) and the front cortex.

It would seem, therefore, that certain, specific areas of the brain are used by one and all for the mother-tongue, but that when a foreign language is learnt (except when it is learnt as a young child) the principal "language" areas of the brain are often off-limits for the new language, and other, less specialised areas are pressed into service, and these areas vary from one person to the next.

Cultural aspects of brain function

Very recent research carried out at the San Raffaele Hospital in Milan and at University College London, led by Eraldo Paulesu in Milan, has investigated how the brain deals with reading tasks in English and Italian. In many ways, English and Italian are opposites as far as reading is concerned. Both languages use the same Roman alphabet (though Italian only has 21 letters), but Italian is highly "phonetic" in its written form, while English is very much the opposite. In Italian there is basically only one way to pronounce each letter or group of letters. The 33 letters and letter combinations (graphemes) in Italian are sufficient to represent the 25 sounds in the language. English, on the other hand, has 1,120 graphemes to represent its 40 sounds, and of course there is a great deal of confusion and ambiguity in the system. After just six months of school, Italian children can read extremely accurately, while after three years of schooling, English mother-tongue children are still slower and less accurate.

The researchers looked at how university students read words in Italian and English. Mother-tongue Italian and English students were asked to read a variety of words and non-words in the two languages, and their brain activity was monitored using PET scanning techniques. Italians proved to read words and non-words faster than the English subjects, even when the non-words were derived from English words (such as "marnet", "connage" and "afton"). And while the Italians still coped with non-words and international words derived from Italian faster than those derived from English, the English students were consistently slower and showed no differences in reading speeds for the different categories of words and non-words.

The researchers found that all of the subjects were using a common brain system when reading, the system – as expected – being based around the pre-frontal cortex, the upper, middle and lower temporal areas (all in the left hemisphere) as well as the upper temporal gyrus in the right hemisphere. However, significant differences emerged between the two groups of subjects. English readers tended to show greater activation of both the lower left temporal region and the frontal gyrus. Both of these areas are involved in word retrieval during reading and naming tasks. On the other hand the Italians showed a great deal of activity at the junction between the upper temporal gyrus and the lower parietal lobe (an area still closely connected to the common system used by both subjects). The diagram highlights these differences in greater detail, though a full picture of the differences is curbed by the two-dimensional nature of such a representation.

A recent article published in the Italian newspaper Corriere della Sera rather oversimplified the situation with its headlines "English speakers use two areas of their brain … Only one part of the brain is needed to speak Italian", but the differences are nevertheless significant. Reading in English is clearly a more complex task and need to involve more areas of the brain.

Conclusion

Little by little neuroscientists are finding out how our brains work with language and precisely which parts are responsible for certain tasks. Of course there is still a vast amount of research to be done, and at present there are probably no significant implications for English language teaching. Nevertheless, it is perhaps helpful to know that our students will be pressing into service areas of their brains that have not been "designed" to cope with language. Perhaps one day we will know whether the better language learners tend to use a certain part of their brains and if there are ways the more suitable areas can be "stimulated". And perhaps the time will come when we will be able to encourage students to develop reading skills in English that make a "fuller" use of the brain. Neuroscientists will probably have a lot to tell us even in the near future.

References and further information

   Published in Modern English Teacher (Vol. 10/2 March 2001) Pearson, Harlow, UK.