THREE in four headteachers say young children's speaking and listening skills have deteriorated in the past five years.
The 121 heads polled felt the speech of three-year-olds was suffering because they spent too much time watching television alone, said the National Literacy Trust and the National Association of Head Teachers.
The trust is now planning a pound;2 million campaign to urge parents to talk more to their toddlers. Neil McClelland, the trust's director, said:
"Children are now less capable of listening to each other, less capable of listening to adults and are less able to speak.
"People need to talk to children from a very early age. Parents could discuss what children see while they walk along together or encourage children to talk while they are playing."
The survey will fuel concerns about young children's speaking skills. Literacy consultant Sue Palmer said: "No one wants to demonise television. But television does not teach children their language: there has to be interaction. To me this is a time bomb that lies under our education system."
The Effective Provision of Pre-School Education project, which is tracking the development of 2,800 children over five years, has found that the way parents talk to their children can close the educational gap between affluent parents and the less well-off.
Teachers are already being targeted to help improve young children's language skills. The Qualifications and Curriculum Authority is rewriting its guidance on teaching speaking skills and the National Union of Teachers is introducing a course in teaching speaking and listening.
* Children's interest in TV should be harnessed to help them to learn to read, suggests Jackie Marsh of the University of Sheffield.
Ms Marsh asked 78 families of nursery-aged children in a working-class community about their reading and television habits.
She found that children were avid fans of television and cartoon characters, but their nursery had no reading materials about these figures. She said that, although the children benefited from the more "middle-class" books at the nursery, they might be more enthused by TV-based books.