Baby Talk
Have you ever wondered why almost everyone speaks differently to a little child? Our voice sounds higher, our pitch becomes more variable, we speak slower and more deliberate. Changes in the way we speak when interacting with a baby or toddler is so widespread we even have a special name for it: infant-directed speech. But most of us probably know it as baby talk. Baby talk is so distinct we can even recognize it in a language we don’t speak. Why do otherwise sane individuals almost sound like simpletons when addressing our little fellow human beings? The answer is simple. Our babies make us do it because it helps them learn language.
Let me explain.
Before my granddaughter was born, I pictured babies as sponges, soaking up information from their social environment, trying to figure out what the world is all about. But as I recently learned, babies are much more than passive vessels of information. Of course, to have become a grandmother I had to be a mother first, so in a way it seems a little odd that I recently changed the way I see babies. But there it is. My renewed focus on babies probably has a lot to do with my recent interest in the origin of language. And to understand the origin of language we need to begin at the beginning. With our babies.
Because raising human babies is so singularly difficult, evolution had to come up with a special trick to make it possible for us to raise them. As it turns out, that special trick is language. Language allowed our ancestors to communicate their need for help in raising exceptionally needy babies, so creating the rich social environment in which human children thrive. And those needy babies actively manipulate the way we interact with them to advance their own learning.
When we use baby talk on babies, they are much more likely to take notice and, if lucky, reward us with a big smile. Because we now have the baby’s attention, we keep interacting so that the baby is exposed to more of our language. So, by encouraging us to speak differently to babies, we spend more time with them, which assists their brain with figuring out how that language business works.
We know that this is not just some excuse that someone came up with to explain why we behave weirdly towards our little human beings because of a neat study that tested how babies react to infant-directed versus adult-directed speech. In the study, published in 2020 in the journal Cognition, Gay Soley and Nuria Sebastian-Galles, tested 12 to 15 month old babies from Türkiye and Spain with animated ‘adults’ and ‘toddlers’ to see if they could tell when someone used incorrect speech. If the characters where not looking at each other, the toddlers didn’t care what kind of speech was used for whom. But if the characters were looking at each other, then the toddlers recognized what the authors called ‘incongruent’ speech. In other words, an adult using adult-directed speech when interacting with a toddler or using infant-directed speech towards an adult. It clearly matters to babies and toddlers how they are addressed, and they recognise it when the wrong kind of speech is used even if they are not at the receiving end.
And there is more.
Before they can even make sounds remotely similar to words, babies as young as 3 to 4 months old use the same sound to express different emotions. Such so-called flexible emotional meaning is a key foundation for language. Just think about how the context changes the meaning of a particular word, or the way we say the same word depending on our emotional state. If we ignore cries and laughter, which express specific emotions, the baby’s facial expression when making a particular sound results in a different response from the caregiver. If the sound is combined with positive baby facial expressions, the caregiver is more likely to encourage the baby by smiling or imitating the sound. If, on the other hand, the same sound is combined with negative facial baby expressions, the caregiver will try to change the situation by picking up the baby or comforting it in a different way.
The authors of the study, which was published in the Proceedings of the National Academy of Sciences in 2013, Kimbrough Oller and colleagues, argue that these early flexible sounds give the baby a powerful ‘practice space’ for language: they let the infant explore speech-like vocal control, meaning, and turn-taking long before actual words appear. Key are the interactions with the caregivers. Because they respond differently to the same sound depending on the baby’s facial expression, the baby experiences how similar sounds can lead to different social outcomes, so building the foundation for communication via sounds.
Clearly, babies manipulate us much more than we may think, all to help them master that unique human characteristic: language.
If you want to learn more about how babies learn language from interacting with caregivers, then look up the 2025 paper by Joseph R. Coffey and Jesse Snedeker: https://doi.org/10.1017/S0305000924000692[Opens in a new window]