Researchers looked at 7- to 12-month-old infants and found that speech from people around them stimulates areas of the brain that coordinate and plan the motor movements necessary for speech.
"Most babies babble by 7 months, but don't utter their first words until after their first birthdays," study author Patricia Kuhl, co-director of the Institute for Learning and Brain Sciences at the University of Washington, in Seattle, said in a university news release.
"Finding activation in motor areas of the brain when infants are simply listening is significant, because it means the baby brain is engaged in trying to talk back right from the start and suggests that 7-month-olds' brains are already trying to figure out how to make the right movements that will produce words," she explained.
The study included 57 infants and used a type of brain scanning technique that is completely safe for infants, the authors noted in the news release.
The findings, published July 14 in the Proceedings of the National Academy of Sciences, show the importance of talking to infants before they start to speak.
"Hearing us talk exercises the action areas of infants' brains, going beyond what we thought happens when we talk to them," Kuhl said. "Infants' brains are preparing them to act on the world by practicing how to speak before they actually say a word."
The U.S. National Institute on Deafness and Other Communication Disorders has more about speech and language development in children.