Anyone who’s ever tried talking to a baby has immediately realized two things about the interaction: The first is that the infant has no idea what you’re actually saying. The second is that you would never talk to a grown-up that way. Your voice gets higher, your speech gets slower, you use shorter phrases with longer pauses, and your pitch fluctuates in a way that would sound ridiculous in other contexts. In fact, it starts to sound more like music!
But it turns out there’s a good reason why we start using this style of speech when we’re around infants, and it stems from the fact that, despite their best efforts, infants are unable to understand most of what we’re saying. That means that we have two goals in communicating with babies: Over the long term, we would like to help them learn the language, and in the short term, we want to make ourselves understood as best we can. Infant-directed speech (as it’s called by scientists) accomplishes both of these goals.
The Music of Language
Even if they don’t understand what “mommy’s little angel” means in a specific sense, the overall sense of “I love you and will care for you” can come through the tone of the voice. This tone, or prosody, is the feeling behind the words, and helps to convey the meaning in a more musical way, through pitch, timing, and timbre, rather than individual words and syntax.
We use prosody in everyday speech; to distinguish statements from questions, to emphasize words, or to convey emotions (contrast “JOHN went to the store, vs. “John went to the STORE” vs. “John went to the store?” vs. “John went to the store!”). This music of language has the same function in infant-directed speech, and helps the infant understand whether we are trying to comfort them, play with them, or put them to sleep.
Over the long term, we also want to help babies to understand their native language. Infant-directed speech helps with this too. By emphasizing important words, over-articulating, and slowing down, the adult assists the infant in parsing out their language and directing their attention to important features. It can also facilitate their understanding of conversational turn-taking, and helps the infant to know when it is their turn to chime in.
This sing-song speech can help a baby learn their native language, but actual singing can be even more effective in some ways. There’s evidence that infant-directed singing can hold attention better than speech, and lead to greater engagement. Moreover, the rhythmic and pitch regularities of music can facilitate the ability to pick out individual words, and help train the brain to be better at recognizing acoustic markers in both speech and music – it’s the first step to the superior language perception and production we find in trained musicians.
So both sing-song speech and singing songs are not only natural ways of communicating with a baby, but it helps the infant learn more about their language. It’s just one of the ways that music and language work together to help us communicate.
Dr. Sean Hutchins is a neuroscientist and the Director of Research at The Royal Conservatory of Music in Toronto. He received his Ph.D. from McGill University, studying music and the mind. His current work examines the role of musical training and experience on cognitive and linguistic abilities.