Thousands of children who fail at school and are shunned by their peers because they have a little-known language disorder could be saved by a brain test being developed by scientists.

Researchers at the University of Manchester are developing the test to measure electrical activity in the brain which would allow children at risk to be targeted with intensive language and speech lessons when very young, preventing long-term social and academic problems.

Up to 100,000 children in Britain suffer from a specific language impairment (SLI), a disorder in which they have difficulty with the development of language which cannot be explained by other disabilities such as hearing loss, low intelligence or poor teaching.

Professor Valerie Newton, of the Centre for Human Communication and Deafness, at Manchester, said: "These children have difficulty in distinguishing speech sounds and because of this are often thought to be badly behaved and labelled as stupid and naughty."

The study is funded by Action Research, a research charity. It involves 144 children, aged 6 to 11, one-third of whom have SLI. About 12 per cent of five-year-olds are believed to suffer speech and language delay.