The Basic Skills Agency (BSA) has defended its decision to spend pound;1 million on press and television adverts that encourage parents to talk to their young children.
The Wales-only adverts, some of which have been scheduled in the prime-time slot during Coronation Street, are designed to improve the talking and listening skills of babies and toddlers to prepare them for school.
The BSA commissioned the campaign after it found that communication skills among young children had declined sharply during the past five years.
The National Confederation of Parent Teacher Associations (NCPTA) has questioned the cost effectiveness of such a campaign but it has been welcomed by the National Association of Head Teachers (NAHT) Cymru.
In 2002 the BSA conducted a survey of more than 700 headteachers in Wales.
Although based on anecdotal evidence, a clear pattern emerged.
Some 56 per cent of teachers said their pupils' ability to listen and respond to instructions had deteriorated, while two-thirds said fewer children could speak audibly and be understood.
And 93 per cent of teachers said it was "absolutely essential" to listen and respond to young children under three years old.
The BSA's director Alan Wells said: "If you grunt at a child it will learn to grunt back. If you speak to them in a more fluid way they will imitate.
We're trying to remind people that that's important."
He added: "The budget for these adverts is a relatively small amount compared with the money spent helping pupils to catch up after they have failed to acquire these skills.
"We've got to communicate using modern technology and modern ways."
Mr Wells said poorer communications skills were down to cultural changes that meant parents were busier and had less experience of good parenting.
They also felt "disempowered" by the education system and did not know what they should and should not do.
The campaign has been endorsed by education and lifelong learning minister Jane Davidson.
But Margaret Morrissey, spokesperson for the NCPTA, said: "They talk as if parents never have these conversations. It's a little bit unfair because probably 90 per cent of parents are always talking to their children.
"The BSA has got to be careful it's not spending far too much of its resources on television adverts that tell parents to do something they already do."
In contrast, NAHT Cymru director Anna Brychan said: "This problem is serious enough to warrant an investment of this kind.
"Our members have noticed a marked decrease in the ability of children who come into school for the first time. We welcome the fact that the BSA has recognised the problem, but what's really needed is parenting classes - active hands-on help."
The television adverts, which show a person talking enthusiastically to someone out of sight who turns out to be their young child, also promote a free advice pack for parents.
The campaign is the fourth funded by the Assembly government to improve basic skills.