Schools should teach pupils to speak eloquently to help dispel the myth of the "grunting teenager", a former Labour government adviser has said.
Being able to talk well is vital if young people are to be successful in life, with employers calling for youngsters to have good communication skills, according to Peter Hyman.
He suggested that speaking is an "undervalued" part of literacy and not enough classroom time is spent on it.
Mr Hyman, who previously worked as an adviser to Tony Blair, told the Times Educational Supplement (TES): "Speaking eloquently is a moral issue because to find your voice both literally and metaphorically and be able to communicate your ideas and your passions is crucial to how they are going to be a success in the world.
"If you can speak and articulate yourself properly that will happen.
"But it's also the number one issue that employers put in all their surveys: they want good oral communication."
He added: "We've got to dispel the myth of the grunting teenager, the monosyllabic teenager that make employers say 'I've got this person who I know on paper is quite good, but they can't string a sentence together.'"
Mr Hyman, who now runs School 21, a new free school in Newham, east London, expressed concerns that there is a general move away from encouraging pupils to develop good communication skills.
A fashion for quiet classrooms is wrong and pupils should spend time discussing ideas and debating with each other, he insisted.
"I think some people out there think the silent classroom is the good classroom, but the silent classroom is the death of learning, unless there's a particular reason for it."
Mr Hyman added: "I think there's too much of a fashion now of saying 'the quieter the better, that shows you've got behaviour under control'.
"I think that is completely the wrong way to go and we've got to put speaking up there on a completely equal footing with reading and writing."
He criticised a decision to remove pupils' speaking and listening results from their final GCSE English grade, saying that oral skills are still considered a key part of foreign language courses.
Mr Hyman's school is currently taking part in a pilot project with Cambridge University which is looking at different ways teachers can improve and test pupils' speaking skills.