Before they start to babble themselves, babies would rather listen to other babies “talk” than listen to adults.
The findings are important, researchers say, because an attraction to infant speech sounds may help to kick start and support the crucial processes involved in learning how to talk.
The discovery could also potentially offer new avenues to help infants with problems such as hearing impairment that hinder the development of their language skills.
‘I Can Try That!’
For a new study, researchers conducted a series of experiments with 6-month infants where they played a repeating vowel sound that mimicked either those made by an adult woman or those made by a baby. The sounds were created using a special synthesis tool.
By measuring how long each sound held the infants’ attention, the researchers discovered that the babies had a clear preference for the sounds that mimicked the infant. On average, the infants listened to the infant vowels almost 40 percent longer than the adult woman vowels.
The preference was not because the sounds were familiar—the babies who took part had not started babbling yet—so the infant-like vowel sounds that they heard were not yet part of their everyday listening experience.
Some babies showed their interest in other ways. They met the adult vowel sounds with fairly neutral, passive faces. But when they heard infant-like sounds, they would smile or move their mouths as they listened, or do both. They seemed to recognize that this was a sound that they could try to make themselves, even though they probably had never heard anything like it before.
Finding Their Own Voice
Caregivers may already know this on an intuitive level, says Linda Polka, professor in the School of Communication Disorders at McGill University and senior author of the study published in the journal Developmental Science.
“Perhaps, when we use a high, infant-like voice pitch to speak to our babies, we are actually preparing them to perceive their own voice.
“As adults, we use language to communicate. But when a young infant starts to make speech sounds, it often has more to do with exploring than with communicating . . . in fact babies typically vocalize when they are alone, without any interaction or eye contact with others.
“That’s because to learn how to speak babies need to spend lots of time moving their mouths and vocal cords to understand the kind of sounds they can make themselves. They need, quite literally, to ‘find their own voice’.”
The Natural Sciences Engineering and Research Council of Canada funded the work.