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Baby talk could be key to language
By Simon Hooper for CNN
Baby talk may have developed as a way of allowing mothers to reassure their infants.
on CNN International on Saturday, Jan. 1 at 12.30 and 20.30 CET.
(CNN) -- A Florida anthropologist believes she can explain the origin of "baby talk," and claims it could have triggered the development of language far earlier than commonly believed.
Dean Falk, professor of anthropology at Florida State University, says the universal phenomenon of mothers talking to their babies may be linked to two other crucial steps in human evolution -- walking upright and the development of bigger brains.
According to Falk's theory, which is published in this month's edition of the journal Brain and Behavioural Sciences, that would mean that language could have begun to develop among humankind's hominin ancestors as many as 1.6 million years ago.
Modern humans appeared around 200,000 years ago, and most anthropologists believe that complex language may have existed for only half that time.
But Falk argues that "motherese" may have its origins in the need for mothers to maintain contact with their infants at a stage of evolution when a direct physical link was no longer possible.
As the early members of the human family stood upright, important changes occurred to their physiology, with the pelvis narrowing as the brain grew bigger. This led to babies being born earlier, at a time when their heads were still small enough to pass though the birth canal.
But that also meant that newly born infants were less developed and more dependent on their mothers.
While the offspring of primates can cling to their mother's hair and ride on her belly or back, human infants had to be carried everywhere by their increasingly hairless mothers.
Since mothers would have to put their babies down while foraging for food, Falk suggests they could have started making noises to reassure them.
Those that made the most successful sounds would have had a higher survival rate because it allowed them to gather more food and prevent their babies from making noises that might attract predators.
"Motherese," explains Falk, is "characterized by a simplified vocabulary, more repetition, exaggerated vowels, higher overall tone, wider range of tone and slower tempo."
"The epiphany for me was that I knew chimp mommies don't make these noises, so I knew something happened during evolution," says Falk.
"The missing puzzle piece was bipedalism. We stood up; we lost hair. It was then that babies could no longer hang on to their mothers. Mothers had to hang on to their babies. That was a eureka moment."
As mothers came to rely on vocalizations to control their infants, they would have developed specific meaningful sounds that would gradually have blossomed across communities into language, Falk says.
Infants as young as seven-months-old can begin to understand basic linguistic rules and develop vocabularies. Experts believe their ability to learn language could hold vital clues to the development of human communication.
"The behavior of chimp mommies and babies and human mothers and infants are delightfully identical in many ways -- the gestures and the facial expressions -- but we are dramatically different in other ways," said Falk.
"We vocalize continually in a way that helps babies begin to learn language by the end of the first year. I wanted to find out why we are the only animals that talk, and this need to pacify our babies as humans evolved may be the reason."
Professor Robin Dunbar, an evolutionary psychologist at the UK's University of Liverpool, told CNN that Falk's theory sounded "extremely plausible, at least as a mechanism for getting generic communication of the babbling mode off the ground. Once you have that, it's a very small step to its being used by adults, and then to having meaning bolted onto the sounds."