Children learn to speak language in an extraordinarily short period of time after they are born.

How is it that language is acquired this quickly?

There are five basic stages of language acquisition:

1. Cooing: Appears at about 6 months or so. All infants coo using all the phonemes from every language. Even congenitally deaf children coo.
2. Babbling: Appears at around 9 months. Infants are starting to selectively use the phonemes from their native language.
3. One-word utterances: At around 12 months, children start using words.
4. Telegraphic speech: Children start making multi-word utterances that lack function words. (about 2 years old)
5. Normal speech: By about 5-6 years of age, children have almost normal speech

Is the ability to learn language innate, or is it the result of children being exposed to lots of language early on?

Nature:

• Perception for speech sounds is better than perception for other sounds

• Congenitally deaf children will learn sign language at about the rate that normal children learn spoken language, and will progress through roughly the same stages.

• Children are not exposed to as rich a variety of speech as they are able to develop.

• Parts of the brain seem to be specialized for language processing

• Parts of our physiology (larynx, highly manipulable tongue) seem to have no purpose except to facilitate the use of speech.




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Chomsky hypothesized that children have a built-in system to aid in the acquisition of language called a language acquisition device.

The LAD can be thought of as a system containing a large number of switches that determine the features of the native language.

For example, there would be a switch for describing whether the language is SVO (English), SOV (Japanese), or some other combination.

Critical period:

There appears to be a critical period for language acquisition, that corresponds roughly to the time before puberty. After puberty hits, people will never learn a language like a native speaker will.

In other words, if you’re not exposed to language as a child, you won’t acquire it all that well, no matter how predisposed your cognitive system may be to learn it.

Hypothesis testing:

An attempt to integrate nature and nurture.

As kids are exposed to language, they form "hypotheses," which are kind of like tentative rules for the language. As these hypotheses are confirmed or disconfirmed, they are modified appropriately.

The nature side of the equation provides the biases that guide what features of language kids pay attention to.

Imitation: Pretty self-explanatory.

Modeling: Children sound like the adults around them, such as by sharing accents and idioms. Adults use child-directed speech to make themselves easier for children to understand.