Talk to Me Baby

We’ve all been there. You’re seated at a restaurant and the baby nestled in a high chair at the next table is staring at you. You raise your eyebrows, scrunch your nose or widen your eyes and break out your brightest grin. You begin a pronounced wave and give them your sweetest, “Hello there,” hoping for a gummy smile in return.

Imagine instead holding a child. You shuffle your arms into a protective cradle, cuddle the baby into your chest and begin the classic cooing that naturally comes out at the sight. When you’re rewarded with a giggle or a babble, it’s an instant prick of euphoria. That instinct you have to change your speech style is called infant-directed speech.

Jessica Hay, Ph.D., is a professor at the University of Tennessee whose research focuses primarily on early language acquisition and speech perception. She runs the Infant Language and Perceptual Learning Lab to explore how infants learn elements of language during early development. “It’s not just that we use a higher pitch voice with kids. In fact, pitch seems to be a little less predictable in infant-directed speech than it is in adult-directed speech. We use a wider range of pitches than we do when speaking to adults. So, there’s more variability,” says Dr. Hay. “We tend to use longer pauses, shorter phrases and a more consistent tempo when we’re speaking to infants. Everybody wants a baby to smile at them, right? And it is actually the case that this change and variation in pitch is more likely to elicit positive reinforcement from the baby.”

But there is more happening than we might realize, much more than a feel-good moment for the adult. The instinct to engage in infant-directed speech is rooted in a constellation of dynamic interactions coming together that play an important role in the development of language and conversation skills.

“You’re giving them something to focus on that is not just attention grabbing and maintaining; it actually supports and facilitates language learning. But I don’t think that’s something we’re conscious of,” says Dr. Hay. We don’t make the deliberate choice to alter our speech because we realize they’re learning from it, but it’s a natural side effect of our instincts at work.

“With infant-directed speech, in addition to having these sort of exaggerated intonational contours, we also tend to highlight important features in speech. For example, part of slowing that tempo down is that we tend to do a bit more hyper articulation of our speech sounds. Different languages have different vowels, right? And if all the vowels were right on top of each other acoustically in the sound, it’d be hard to differentiate them. Well, infant-directed speech actually tends to produce vowel spaces that are more distributed, so your ‘ahs’ and ‘oos’ are more separate from each other than they are in adult-directed speech.”

Those instinctual manipulations have an impact. Dr. Hay’s research shows that when parents or guardians use more distinctive vowel spaces when speaking to their babies, the infants have better speech discrimination skills in the lab. Those speech discrimination skills can predict things like vocabulary size. For example, kids who can better distinguish the sounds used in their native language have a larger vocabulary a year later.

It’s not only our pitch that changes, of course. Even adults who tend to speak to children more “adult-like” utilize tools of infant- and child-directed speech where syntax and grammar are simplified. This all plays a role in helping kids understand the phonological system of their language. “When we speak to each other, words flow continuously, one to the next. One of the jobs of infants is to find where the word starts and stops. It turns out that kids are pretty sophisticated doing this. They can actually track the likelihood that sounds will go together, but they’re better at doing it if the speech is infant directed.”

We experience a similar instinct when we talk to animals, but there are some important distinctions in pet-directed speech that you can pick up on if you know what to listen for. “There are a bunch of acoustic features that change in the speech that we use with infants, and many of these change in the speech we use with pets. These intonational exaggerations serve sort of a similar role for both: that fluctuation and pitch really grab attention.” But when we crouch down to coo over a puppy, we don’t expect it to ever speak back. That intuitive knowledge creates the natural differentiation.

“One of the things that’s curious about pet-directed speech is that the vowel space isn’t enlarged. You’ve got that intonational contour, the variability and the pitch, but those features of speech that might help an infant learn language aren’t exaggerated or highlighted in pet-directed speech. Because the goal isn’t for a dog to learn speech,” says Dr. Hay.

The auditory element is perhaps the most familiar. It’s easy to imagine the exact tone of voice you might use to tell a dog it’s a good boy or to gush about how cute your niece or nephew is. But infant-directed interactions are not unimodal. “It’s not just the speech stream,” says Dr. Hay. “It’s hard to engage in exaggerated speech without the facial movements that are associated. So, they’re getting multisensorial input. The body movements and facial movements help kids start to integrate across modalities.”

It’s not that there is one right way to speak to kids, and individual personalities will always play a role in communication style. But the subconscious adjustments you make without thinking about it do a lot of the work. Simply mimicking sounds back and forth is a way of bonding. When a child babbles, smiles or gestures in return, it’s a natural reinforcement to keep going.

And it can’t be replicated by television programs or digital engagement. “Infant-directed speech is a contingent interaction. So, you talk, the kid talks, you talk, the kid talks. It’s the back and forth that teaches infants the beginnings of conversation,” says Dr. Hay. “You can get a lot of pitch variation in a media format, but it’s not responding to you. It’s not reinforcing the kids’ own productions.”

It’s natural for new parents, or adults who haven’t spent much time with children, to experience insecurity about what they’re supposed to say to babies. Dr. Hay’s advice? Simply talk to them, or at them, even. “You can just narrate your day; chatter with them. They’re going to get a lot of what they need through that interaction.”

Next time you’re sitting on the subway, waiting in line at the coffee shop or taking a walk and you spot an infant looking your way, be sure to say hello.