Language acquisition starts before babies utter their first words. Even in the womb, they jump in response to noises, such as fireworks and loud bands; they eavesdrop on their mother’s conversations. Within just hours of birth, newborns recognize their mother’s voice, along with stories and songs they’ve heard in the womb. They can even distinguish their native language from a foreign one (for example, French versus Russian). They enter our world prepared to learn any of the 7,000 languages spoken and signed around the globe.
Though language begins as a flowing melody of sounds and sights (for signers), babies quickly learn to find meaningful patterns in the speech they hear. Where does one word end and the next begin? How do building blocks like words come together to form sentences? Research suggests that by 4.5 months of age, they’re on the way to finding words in the stream of speech that washes over them. They start by recognizing their own name (“IRVing” is different from “AnnETTE”); in very little time, they distinguish their name (e.g., “IRVing”) from other names with the same stress pattern (“WILson”). Their names and other frequently occurring words – like “mama” – serve as anchors into the speech stream (Bortfeld et al. 2005).
Babies also compute statistics on the sound stream to find the words. In one classic study, 8-month-old babies heard a string of nonsense sounds (“bidogolabidomanelamebido”) for just 2 minutes; surprisingly, they learned that the combination of sounds “bido” occurred together and more frequently than “gola”. As tiny statisticians, they use these skills to find the sounds that together make up words (Saffran et al. 1996). Babies also use their keen detective abilities to find the beginnings and ends of sentences. For example, the word “book” is pronounced differently in the following two sentences: “He took the book off the shelf” and “Off the shelf, he took a book”. Babies of just 4.5 months know that the vowel gets stretched in a word when it occurs at the end of the sentence (Jusczyk et al. 1992).
However, attention to sounds takes babies only so far. They next need to figure out what the sounds mean. By six months, infants attach the word “mama” to their own mother and not to just any woman. As their internal vocabularies expand, learning what words mean can be complicated. A classic example is what might happen if we were in a foreign country and saw a rabbit hop by. A native might say “gavagai” and we must determine what that means. “Rabbit” seems the obvious guess, but it might not be right. Among other possible candidates, “gavagai” could refer to “hopping” or “ears.” Despite the daunting nature of this task, by 12 months of age, babies seem to interpret words as labels for whole objects (like rabbits) as opposed to parts (like ears) or actions (like hopping). And once they learn a cadre of object words, they then turn their attention to words for actions (verbs) and properties of objects (adjectives). Most babies say their first words around 12 months. By 18 months, many have a vocabulary of 50 or more words in their repertoire and understand twice that number.
Learning words is a stunning achievement that starts out slowly and gains pace between 18 and 21 months when children seem to become what Pinker (1994) called “vacuum cleaners for words.” It is at this time that they also take the first step that marks true language acquisition: they begin to put words together to make sentences. They know more about their language than what they can say – just as you could understand more in a foreign language than you could speak. So while their first spoken words appear at around 12 months of age, they may already understand hundreds of words.
By 18 months, toddlers can understand fiveand six-word sentences when they may be saying only one or two words at a time themselves. One example of their grammatical abilities comes from a study looking at whether toddlers pay attention to the order of words. English is very sensitive to order as a clue to meaning. History would be quite different if “Caesar killed Brutus” rather than “Brutus killed Caesar.” Picture an oversized TV screen, split between two moving images. The left image shows the Cookie Monster hugging Big Bird, the right image Big Bird hugging Cookie Monster. Babies watch the screen with rapt attention. When they hear “Where’s Big Bird hugging Cookie Monster?” they look more at the right side of the screen than at the left. This indicates that toddlers are sensitive to grammar. They use the order of the words in English to figure out who is doing what to whom.
Language learning progresses as children learn the rules of grammar, the ways in which words can be reassembled to make questions from statements (“You can go” versus “Can you go?”) and the ways in markers are added to contradict a statement (“You can NOT go”). These facts about sentences take time to learn. Another example is learning to use wh-words in the English language. The word “what” requires a response about an object (Question: “What did you eat last night?” Answer: “Steak”), but words like “why” and “how” require entire explanations (Question: “Why did you eat a steak?” Answer: “I could have eaten a bear”). And wh-words can only appear in certain places within sentences. Children don’t use and understand these words until well into the third year of life.
Babies are sponges when it comes to learning languages. There is much more going on than what we see. And remarkably, they are as good at learning two or more languages as they are at learning one. Before they can tie their shoelaces or be left alone, children are solving one of the most complex tasks in human nature, acquiring an ability that distinguishes us from all other species on the planet: they are learning language.
- Bortfeld, H., Morgan, J. L., Golinkoff, R. M., & Rathbun, K. (2005). Mommy and me: Familiar names help launch babies into speech steam segmentation. Psychological Science, 4, 298 –304.
- Golinkoff, R., & Hirsh-Pasek, K. (1999). How babies talk: The magic and mystery of language acquisition. New York: Dutton/Penguin.
- Hirsh-Pasek, K., Golinkoff, R. M., & Eyer, D. (2003). Einstein never used flashcards: How our children really learn and why they need to play more and memorize less. Emmaus, PA: Rodale.
- Jusczyk, P., Hirsh-Pasek, K., Kemler Nelson, D., Kennedy, L., Woodward, A., & Piwoz, J. (1992). Perception of acoustic correlates of major phrasal boundaries by young infants. Cognitive Psychology, 24, 252 –293.
- Pinker, S. (1994). The language instinct: How the mind creates language. New York: William Morrow.
- Saffran, J. R., Aslin, R. N., & Newport, E. L. (1996). Statistical learning by 8-month-old infants. Science, 274, 1926 –1928.
Back to Developmental Communication.