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When we hear people using baby talk, most of us feel like we're not hearing what you might call a deep conversation... It's all high-pitched, sing-songy sounds and, "Peekaboo!" and, "Where'd the ball go?" and, "Is that a kitty-cat?" It doesn't exactly sound like a TED talk.

But even though it sounds kinda silly, there is a reason that it starts coming out of our mouths as soon as we see those adorable chubby cheeks. Ask the internet or a parent from an older generation, and you might be told that using baby talk with kids is bad for them. They claim kids who hear baby talk won't have the opportunity to learn proper adult speech.

But research actually suggests the opposite is true. Baby talk, known to scientists as infant-directed speech, really does seem to help babies with their language development. Infant-directed speech is the unique way of talking that we use with babies.

It has that really recognizable tone and rhythm: our voices go up in pitch, we use a wider range of pitches to sing-song through phrases, and it has slower, more exaggerated vowel sounds. The general term for these tonal and rhythmic elements of speech is known as prosody. And research shows the prosody of infant-directed speech can help with a baby's attention and language learning.

We've known for a long time that babies pay more attention to higher-pitched voices. And in a study published in 2018, scientists suggested that infant-directed speech could be more attention-grabbing because it's less predictable than the speech we use with adults. But once we've got a baby's attention, baby talk's slow rhythm and exaggerated vowels might play another role.

For example, a 2010 study showed pictures of things like cups or bunny rabbits to 19-month-old infants. The babies were told, in a baby talk-y voice, to look at a specific picture. And the more baby talk-y the instructions were, the more likely the babies were to look at the right picture.

The idea is basically that speaking this way helps babies split up an endless, featureless stream of sounds into chunks that have meaning. You know, words. And other research has shown that isolated words are easier to learn.

All told, there's quite a lot of evidence to suggest that prosody really does make a difference in helping babies pay more attention to parental speech and gain linguistic skills. But prosody isn't the whole baby talk story. There's also discussion around whether infant-directed speech is grammatically simpler than adult speech.

And this seems to be where some of the controversy comes in. Here's the thing: infant-directed speech does have a lot of short phrases and sentences. And historically, researchers thought that this meant it was a simpler kind of input that let babies learn by using easier forms of language.

But as researchers argued as far back as the 1980s, that doesn't necessarily make a whole lot of sense. If baby talk is so simple, how do babies pick up on the more complex rules of grammar? That's probably what the people who tell you to “speak properly” to kids are getting at when they say baby talk is bad.

But even if sentences of baby talk are shorter, they're very grammatically correct. While we might take shortcuts when it comes to speaking with other adults, the grammar we direct at kids is usually much more accurate. And infant-directed speech can actually model many different, but overlapping, grammatical structures, which provides complexity.

This is why we say things like, Where's the doggie?, and then follow it up with a bunch of other statements that basically rephrase the same idea. Like, is that a doggie? Yes, that's a doggie!

Let's pet the doggie! There are other debates about baby talk, too, like whether cutesy words like “choo choo” have any benefit. But when it comes to the prosody and grammar of baby talk, we probably don't have much to worry about.

There's plenty of evidence to suggest that parents change the tone and emotional content of infant-directed speech as the baby gets older, which implies that as infants' developmental needs change, we naturally adjust our way of speaking to them. Baby talk is also a pretty universal phenomenon, which does seem to suggest that it's a normal part of infant development. Kids as young as three have been seen using this vocal pattern with babies.

And while there's a lot of variation in how infant-directed speech sounds across cultures, most cultures do it. For instance, Cantonese and Japanese baby talk don't seem to have exaggerated vowels, but they do have changes in tone and rhythm that emphasize features of those languages. Scientific research might not be able to answer all of our questions about baby talk just yet, but the evidence mostly suggests that it's something we do naturally and something that our babies learn from.

So don't worry about how it sounds! Your baby will be happy to hear it. Thanks for watching this episode of SciShow Psych!

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