Why baby boys babble more than girls in their first year

Study sheds light on gender differences in infant language development

From squeals to vowels, growls and sounds such as 'ba', infants love to communicate. Getty Images

Boys are more vocal than girls during their first year, a study has found.

But girls catch up and overtake them by the age of two.

Infants make a variety of sounds – squeals, vowel-like noises, growls, and short word-like sounds such as “ba” or “aga”. These “protophones” are the building blocks of language development.

However, a study published in iScience has revealed differences in the frequency of protophones between male and female babies.

The findings echo an earlier, smaller study conducted by the same team.

“Boys show higher rates of speech-like vocalisation in the first year of life,” Dr D Kimbrough Oller, a researcher from the University of Memphis, told The National.

He said this could be because there is a higher infant mortality rate among boys, which “imposes a higher priority on signalling wellness to caregivers during that period”.

As the mortality rate decreases for both genders in the second year “the pressure on special fitness signalling is lower for both boys and girls”, Dr Oller added.

“While boys showed higher rates of vocalisation in the first year, the girls caught up and passed the boys by the end of the second year,” he said.

The research on differences between genders was not initially the primary focus of the team, who were looking at understanding the origins of language in infancy.

In the study, researchers analysed more than 450,000 hours of all-day recordings from 5,899 infants using a small recording device.

Dr Oller called it “the biggest sample for any study ever conducted on language development, as far as we know”.

The data revealed that boys made 10 per cent more sounds than girls in the first year.

However, in the second year, female infants made about 7 per cent more.

The findings showed that adults spoke more words to girls in both years.

“We anticipate that caregivers will show discernible reactions of interest and of being charmed by the speech-like sounds, indicators that fitness signalling by the baby elicits real feelings of fondness and willingness to invest in the well-being of infants who vocalise especially effectively,” Dr Oller said.

“We wonder how caregivers will react to speech-like sounds of boys and girls. But they may have to be told which infants are which, because we don’t even know if sex can be discerned in the vocalisations alone.”

Dr Oller emphasised that both male and female human babies have high vocalisation rates, in stark contrast to other species of ape.

“The fact that humans vocalise so much from the beginning of life is a manifestation of the deep human inclination to use the voice exploratorily and communicatively,” he said.

“Both girls and boys deserve parental attention. There is every reason to believe such vocal interaction with babies is good for both the babies and the caregivers.”

Dr Oller told The National that the overall advantage girls are presumed to have in language is small and complex. It is dependent on various factors such as age, circumstances and the number of people involved in conversations.

He said: “Both men and women must be able to talk, so it would make no sense for there to be large differences in male and female language abilities.”