Study reveals risk factors for developing stuttering in bilingual children
22 September 2008
The study, published today in the journal 'Archives of Diseases in Childhood', also found that children who stutter but are not taught to speak English until school have a better chance of recovering from their stutter than children who stutter and are brought up in a bilingual environment.
Stuttering is thought to affect one in 20 children under the age of five, with onset generally occurring between the ages of four and five years. It is believed to have a number of underlying causes: around half of people who stutter are believed to have structural problems in the nervous system, while for the remainder it may arise from social or family circumstances, such as use of a second language in the home.
In many cases, children recover without the need for treatment, but up to a quarter of children who stutter are at risk of developing chronic stuttering, which may persist into adulthood. Professor Peter Howell from UCL (University College London) has been conducting longitudinal studies to identify which children are most likely to have persistent stutters and will benefit most from therapy.
Professor Howell and colleagues studied 317 children aged between eight and twelve years who stuttered, looking at their stuttering history, school test results and whether they recovered from their stuttering or whether the condition persisted. The bilingual children in the sample usually stuttered in both languages.
Of the 38 children who used a language other than English at home, 23 spoke both English and the minority language from birth. Only a quarter of these children recovered from their stutter. The remaining group of 15 children learned English only once they started school; over a half of these children recovered.
"Children who speak both English and the minority language appear to be particularly prone to develop stuttering," explains Professor Howell. "Our results suggest that this risk would be reduced if children who speak a minority language at home wait until they are five to start learning English. Deferring the time bilingual children learn English also improves the chance of recovering from a stutter later in childhood."
The researchers also measured educational attainment in school SATS tests and found that performance was not affected by whether a child had a stutter or not, and nor did it depend on whether a bilingual child learnt English alongside or after a minority language. The same appeared to be the case for social adjustment, such as temperament and social skills, which the researchers determined from reports given by the children's parents.
Professor Howell believes that children who learn two or more languages concurrently in early childhood may be more likely to stutter due to the additional cognitive load surrounding using two languages.
"It's important to monitor a child's development carefully, particularly in families that already have a history of stuttering," he says. "If a child is showing signs of developing a stutter, therapists will advise - if it is an option - whether to hold off teaching him or her English until school."
The research has been welcomed by Norbert Lieckfeldt, Chief Executive of the British Stammering Association (BSA).
"This is immensely important research, and BSA welcomes these findings and the support offered by the Wellcome Trust," says Mr Lieckfeldt. "To this day, the only way to completely overcome stammering is through early intervention in pre-school children. The results will help to identify those children most at risk so that targeted help can be offered quickly, to ensure a lifetime free from stammering."
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Notes for editors
1. Howell P et al. The effects of bilingualism on stuttering during late childhood. Arch Dis Child 2008 Sep 9. [Epub ahead of print]
2. The Wellcome Trust is the largest charity in the UK. It funds innovative biomedical research, in the UK and internationally, spending over £600 million each year to support the brightest scientists with the best ideas. The Wellcome Trust supports public debate about biomedical research and its impact on health and wellbeing.
3. Founded in 1826, UCL was the first English university established after Oxford and Cambridge, the first to admit students regardless of race, class, religion or gender, and the first to provide systematic teaching of law, architecture and medicine. In the Government's most recent research assessment exercise, 59 UCL departments achieved top ratings of 5* and 5, indicating research quality of international excellence.
UCL is in the top ten world universities in the 2007 THES-QS World University Rankings, and is the third-ranked UK university in the 2007 league table of the top 500 world universities produced by the Shanghai Jiao Tong University. UCL alumni include Marie Stopes, Jonathan Dimbleby, Lord Woolf, Alexander Graham Bell and members of the band Coldplay.