Issue date: Thursday 26 June 2003

Mandarin Chinese use more of their brain than English speakers to understand language

Mandarin Chinese speakers use two sides of their brains to understand language, whereas English speakers use just one, according to new findings from Wellcome Trust researchers. The observation may have implications for the treatment of stroke-associated language impairment through drug and other therapies, which are already being investigated.

"Speech is a really complex sound," explains Wellcome Trust psychologist Dr Sophie Scott, who led the project. "As well as understanding words, the brain also uses the way in which words are spoken, such as intonation and melody, to turn spoken language into meaning. This system also has to be robust and flexible enough to deal with variations in speech sounds such as regional accents."

By performing brain scans on volunteers, the research team found that different areas of the brain were able to interpret the different components of speech, such as words and intonation.

They discovered that a region called the left temporal lobe (located by the left temple) becomes active when English speakers hear English. The team believes that this lobe links speech sounds together to form individual words. But, when Mandarin Chinese speakers perceive Mandarin, both the left and right temporal lobes are active. "We were very surprised to discover that people who speak different sorts of languages use their brains to decode speech in different ways; it overturned some long-held theories," said Dr Scott.

The normal function of the right temporal lobe is to process melody in music and speech, so this region 'lights up' when English speakers hear music, as observed using imaging techniques. The researchers do not yet know whether the right lobe is active in English speakers when they hear Mandarin.

Unlike English, Mandarin uses intonation to give completely different meanings to particular words; the word "ma", for example, can mean "mother", "scold", "horse" or "hemp".

"We think that Mandarin speakers, interpret intonation and melody in the right temporal lobe to give the correct meaning to the spoken words," said Scott.

It is not easy to test whether Mandarin speakers have other gifts that set them apart from English speakers, but there is anecdotal evidence to suggest that it may relate to how thought processes operate, according to Scott.

As well as providing an insight into how our brains work, the research could help us understand what happens when people are forced to re-learn their speech comprehension skills - following a stroke or being fitted with a kind of hearing aid called a cochlear implant, for example.

The auditory region is surprisingly malleable, and drugs that influence the communication between nerve cells could be used to affect this plasticity. The connections that have been lost in disorders like stroke need to be re-mapped, and this may be possible through a combination of learning and drug therapy, says Scott.

"There is evidence from other studies that certain drugs affect learning in the brain regions that support hearing and speech. People whose speech perception is affected by stroke often make a good recovery, and even in worst cases they at least are able to understand single words. This suggests that plasticity is possible in humans and that it is something we can improve on," she added.

"It seems that the structure of the language you learn as a child affects how the structure of your brain develops to decode speech. Native English speakers, for example, find it extraordinarily difficult to learn Mandarin," said Dr Scott.

Dr Scott and colleagues will exhibit their research at the Summer Science Exhibition at the Royal Society in London from 1-3 July. Members of the public, including school children, will be able to witness their own brain's ability to tune in to initially unintelligible speech - such as the vocoded speech heard by people with cochlear implants. They will also be able to watch a computer simulation of how different parts of the brain become active as the sounds they hear become more like speech, and see how being able to see a speaker's face makes it easier to understand what they say.

"We live in a world of constant chatter. Speech, in the form of conversations, phone calls, songs, radio and TV assails our ears, yet we somehow manage to make sense of it all without even thinking about it. It is amazing how our brains are able to pick out words and meaning from this confusing cacophony of sound so effortlessly," said Scott.

For more information contact

Shaun Griffin
Wellcome Trust Media Office
Tel: 020 7611 8612
Mobile: 07710 307059
E-mail: s.griffin@wellcome.ac.uk

Notes to Editors

• The Wellcome Trust is an independent, research funding charity, established under the will of Sir Henry Wellcome in 1936. The Trust's mission is to foster and promote research with the aim of improving human and animal health. Website: www.wellcome.ac.uk

• An image of brain regions 'lighting up' in English and Mandarin speakers is available to download. [ 70dpi, 168k], [ 180dpi, 410k], [ 300dpi, 1162k].

• Around two-thirds of people affected by stroke develop a problem with language. Even a minor stroke can have a dramatic effect on language.

• The Summer Science Exhibition is the Royal Society's annual opportunity for the public to come into the Society and meet scientists and engineers at the cutting edge of research to talk informally with them about their work. For more information about the Society and the exhibition please go to www.royalsoc.ac.uk or www.sc1.ac.uk. Dr Scott and colleagues will be demonstrating at Exhibit number 4.

• Researchers from University College London, the John Radcliffe Hospital in Oxford and Hammersmith Hospital in London who worked on the project include Dr Sophie Scott, Professor Stuart Rosen, Professor Richard Wise, Dr Andrew Faulkner, Dr Jane Warren, Dr Yi Yui Meng, Dr Charvy Narain and Dr Galina Spitsyna.