As a parent, what is your most cherished memory? The heart-stopping, life-changing moment you first held your newborn son or daughter in your arms? Their first smile, perhaps, or first faltering steps? Or was it their first recognisable word, pointing proudly at a cat or favourite toy as they finally grasped the uniquely human power of language. Learning to speak is also wonderful for both parent and child because it allows them to tell you what they need without tears or tantrums, simply to ask for a bottle, or to tell you they're hot, cold, tired, wet or - crucially - in pain.
But what if your son or daughter could communicate with you before mastering the power of speech, which typically doesn't occur until they're 12-18 months old? Well, they can, with "baby signing" (or symbolic gesturing, as the experts call it). This non-verbal system, based on the type of hand gestures used by the hearing-impaired, has been around since the early 1960s. But it came to prominence in 1982, when Dr Linda Acredolo and Dr Susan Goodwyn, of the University of California, noticed that babies spontaneously used simple gestures to communicate before they could talk. In the following three decades a vast global industry has sprung up, with baby signing practised by millions of parents across the globe.
The fact that a six-month-old infant can tell their carer it's time for a snack, nap or nappy change is clearly impressive. But critics question whether baby signing has any long-term benefits in terms of language acquisition and cognitive functioning. Some paediatricians even claim that it slows language development because children rely on gestures rather than learning new words. Other critics argue that it's yet another stick for middle-class parents to beat themselves up with - little Thomas not signing yet? What kind of a lazy, feckless mother are you?
Despite the critical voices, baby signing's popularity remains undimmed. And last month, the University of Hertfordshire's School of Psychology published the results of a three-year research project into its effectiveness. The research fellow Elizabeth Kirk, one of the project team, offered free sessions for mothers and babies in Sure Start children's centres (a government programme that brings together early education, childcare, health and family support).
"We held communication sessions where we taught mums signs for words like 'milk', 'more', 'food', 'all gone' and 'where'. Children do pick these up and use them to communicate. And that's not just imitation - they can use them before they start to speak," she says. That's because the muscles children need for intelligible speech don't develop until 12-18 months, while fine motor skills, which allow babies to use their hands in intricate ways, develop from seven to nine months. For example, children usually start pointing at this age. And paediatricians say being able to point is as important a developmental milestone as the ability to speak.
Kirk also says it's a misconception that pre-verbal children can't communicate. "Kids are born communicating," she says. "Their vocalisations and eye gaze, for example. And mums and babies take part in what we call 'proto-conversations' from six weeks, where they take it in turns cooing and responding to each other - tiny babies will imitate their mothers in this way." But she sounds a cautionary note when it comes to baby signing, arguing that its greatest benefit is for socially deprived children. "The main finding of our research is that baby signing only improves language in those who have suffered a language delay because of social deprivation, for example," she says. "It's a massive business and, ironically, the mothers most likely to buy into these products are those whose children are least likely to need it."
Not so, according to Fiona Winterhalder, a London-based baby signing teacher who works with Tiny Talk (www.tinytalk.co.uk). The UK's leading baby-signing organisation, Tiny Talk was founded in 2002 by Katie Main, a primary school teacher who also worked with deaf children. "She taught her seven-month-old son to sign for 'milk', 'food' and so on," says Winterhalder. "Katie's friends were amazed and wanted to learn it themselves."
Winterhalder learnt to sign when she was expecting her first son and then taught him when he was eight months old. She's a passionate advocate of baby signing and, unlike Kirk, believes any child can benefit from it. "I do think baby signing is for everyone, whatever their background," she argues. "It helps all children learn to communicate." Tiny Talk classes welcome mothers and babies from newborns and up, with the first 30 minutes of a group class spent singing and signing nursery rhymes and action songs, with a further half hour of playtime for children and signing tuition for mothers. Many of the core signs they learn are iconic, such as the sign for "car" (hands turning an imaginary steering wheel), while some are less obvious ("potty" is the hand moving up and down the top corner of the chest).
As well as helping babies express their needs, signing can also take the sting out of the infamous terrible twos, says Winterhalder. "We launched toddlers' classes last year, for kids from 18 months to pre-school age. With older children, we're teaching them how to express feelings like happiness and sadness, which helps reduce frustration for both carer and child." Winterhalder has used signing with both her sons and is convinced it helped with their behaviour. "I can honestly say that we've never had tantrums because we couldn't understand each other. We've had them because we do, like the fact they couldn't have any more biscuits, but that's all part of growing up," she says.
Baby signing is also popular in the US, where companies such as Signing Time (www.signingtime.com) and Wee Hands (www.weehands.com) teach infants key elements of American Sign Language. But Dr Michelle Macias, a professor of paediatrics at the Medical University of South Carolina, says the jury is out on its lasting benefits. "I have yet to see any good evidence that it helps babies' language development," she says. "I've heard anecdotal evidence that it does, but some paediatricians argue it actually delays the acquisition of language because babies are using signs instead of acquiring words. The key thing is that if you have a typically developing baby, they will develop their language no matter what."
Macias adds that even slow developers will catch up in their second year, so she warns pushy parents against using signing to give their tots a head start on the pint-sized competition. Instead, she backs its role in establishing the parent-baby bond. "Anything that adds to a parent or caregiver interacting with their baby is good. So for me, the biggest benefit of baby signing is that it encourages parents to get down to their baby's level to play, talk to them and really take time to interact," she says.
Like Winterhalder, Macias can also see potential behavioural benefits. "It could enhance their social-emotional development," she says. "If a baby or toddler is less frustrated because they can tell their mother what they need, that's clearly a good thing." Ultimately, it seems as though baby signing is, at the very least, a fun way for parents to communicate with their pre-verbal offspring. It can also help cement the parent-child bond, reduce frustration, improve behaviour and encourage parents to interact with their children from infancy onwards, which is a crucial part of raising happy, well-adjusted children.