A nine-month old child is typically developing if he can speak even one word. With the benefit of proper scaffolding, he’ll know fifty to one hundred words within just a few months. By two, he will speak around 320 words; a couple months later – over 570. Then the floodgates open. By three, he’ll likely be speaking in full sentences. By the time he’s off to kindergarten, he may easily have a vocabulary of over 10,000 words.
For years, experts have said that the key to jump-starting that development was exposure to tons of language. But the most important lesson from the newest science is this: the central role of the parent is not to push massive amounts of language into the baby’s ears. Rather, the central role of the parent is to notice what’s coming from the baby, and to respond accordingly.
With that in mind, here are just a few of the hottest tips from scientists who study how babies learn language. Throw out your Baby DVDs and your verbal pedometers, don’t obsess about baby sign, and get informed.
1. Let the Baby Drive the Conversation
Language learning begins before infants produce a syllable or understand a single word. At this point, it’s about learning that there is this magical thing called communication. If the baby coos, and the daddy responds, “Is that so?” then the baby will babble again. So the daddy returns, “Well, we’ll have to ask Mom.”
Through this call-and-response pattern, the baby’s brain learns that the sounds coming out of his mouth affect his parents and get their attention – that voicing is important, not meaningless.
Most parents intuit this turn-taking spontaneously – but they don’t all do it equally well. A remarkable study found when four-month-old infants and parents had better verbal turn-taking, that predicted greater cognitive ability when the children were two years old.
2. Recognize the Stages of Babble
No less than eighty muscles control the vocal tract, and it can take a year or more to gain control of. So while babble might sound like gibberish, it’s actually a progression of overlapping stages, as the child learns to master sound production and muscle control.
From birth, children make quasi-resonant vowel sounds. They use the back of the vocal tract with a closed throat and little breath support. At this point, kids may sound like they are fussing when they aren’t; they could just be experimenting with their throat muscles.
Around five months, a baby has enough control to open her throat and push breath through to occasionally produce fully resonant vowels. Soon the baby is adding marginal syllables, consonant-vowel transitions. Rather than “goo” and “coo,” more like “ba” and “da,” using the articulators in the front of the mouth. This is why so many of a baby’s first words start with “b” and “d”: they’re the first proper consonants the muscles can make. However, since the baby still can’t get his tongue, teeth and upper cleft out of the way fast enough, the vowel sounds are distorted.
As early as six months, but typically around nine months, infants start producing some canonical syllables, the basic sound-units of adult speech. The consonant-vowel transition is fast, and the breath is quick. The child is almost ready to combine syllables into words.