Two years ago, one of my dearest and oldest friends had a baby, a sweet little boy born in the summer. He was the first child of my friend group, so I made sure to go visit him that fall, even though school had started back up again and I was already swamped with work. That semester I was taking a psycholinguistics class, and as my friend rocked her infant to sleep, I sat up reading about first language acquisition. It was fascinating to read about how quickly and ingeniously children learn to speak their first language, and it has been even more fascinating watching the process display itself in the speech of this little guy.
Here is a list of some of the milestones of child language abilities:
- 12 weeks – smiles and coos when talked to and nodded at
- 18 weeks – responds to human sounds by turning head and eyes to search for speaker
- 6 months – changes from cooing to babbling sounds
- 8 months – begins to have distinct intonation patterns; begins to make sounds to signal emphasis and emotions
- 10 months – appears to wish to imitate adult sounds (but is not quite successful)
- 12 months – begins to be able to replicate common sounds; simple words (i.e. mamma, dadda) start to emerge; shows signs of understanding some words and simple commands
- 18 months – has definite repertoire of 3 to 50 words; still babbles but now babbling has several syllables and an intricate (language-like) intonation pattern
- 24 months – has vocabulary of more than 50 words; begins to spontaneously join words in original two-word phrases
- 30 months – fast increase in vocabulary; no longer babbles; becomes frustrated if not understood by adults
- 3 years – has vocabulary of about 1,000 words; “produces utterances with grammatical complexity comparable to that of colloquial adult language, although mistakes still occur”
- 4 years – well-established vocabulary; “tends to deviate from the adult norm more in style than in grammar”
Researchers have noted that “one remarkable thing about first language acquisition is the high degree of similarity which we see in the early language of children all over the world.” Babies from every different speech community – even deaf babies – begin by babbling, playing with their vocal tract. Experiments have shown that babies begin to distinguish between different sounds in adult language very early, long before their own babbling starts to distinguish itself. After a few months, though, babies begin to develop “accents” in their babbling and cooing:
Ruth Weir and Jean Aitchison have reported research that demonstrates this tuning. Recorded babbling of an American, a Russian, and an Arab baby was played to mothers. The American mothers could often identify the American baby, the Russian mothers the Russian baby, and the Arab mothers the Arab baby. But none of them could distinguish between the remaining two babies. So the babies, even though they weren’t saying anything meaningful, were evidently making noises that sounded like the language they had been hearing around them.
After this early stage, language acquisition really speeds up. By the age of twenty months, children are really talking, though usually just in single-word utterances (my little friend’s current favorites are “cookie” and “helicopter.”) Around two years old, they start to be able to put words together into two-word utterances that start to look like sentences (I’m imagining phrases like “more cookie” will soon appear.) This is all very basic grammar, and there is ample evidence that even at this early stage, children are beginning to grasp the grammar of their native language. Then they start acquiring vocabulary at lightning speed. Most researchers estimate that the average five-year-old has a working vocabulary of 10,000 words, which means that in the three years between the ages of two and five, they have averaged almost one new word every hour they are awake.
I’m sure any parent who has observed this kind of rapid acquisition in their small children has been amazed (and possibly befuddled.) Linguists, particularly psycholinguists, are pretty fascinated by it as well. There are so many things child language learning can tell us about the human brain and cognition, and the question of how children know what they know has sparked endless debates that won’t be solved any time soon.
Children know much, much more than they are able to say (the same is true for adults, by the way!) If only these astonishing little creatures could explain to us just what’s going on in their heads! Since that doesn’t seem possible, all of us grown-ups will just have to settle for watching, and listening, and trying to understand.
 Adapted from Bergmann, Hall, & Ross (2007). Language files: materials for an introduction to language and linguistics (10th ed.). pp 325, 332. Columbus, OH: The Ohio State University Press.
 Lightbown, P. M. & Spada, N. (1999). How languages are learned (2nd ed.). New York, NY: Oxford University Press USA.
 Jackendoff, R. (1994). Patterns in the mind: language and human nature (p. 102). New York, NY: BasicBooks.
 Jackendoff, p. 103.
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