Language Learnability and Language Development

However, the argument seems fairly simple:

1. A grammar can be abstracted from speech (in this case, English speech) based on observed regularities.

2. We can observe a change in a child's speech as he/she moves from simpler to more complex grammatical forms. So we can identify each such change in terms of the starting and ending forms.

3. For any such changes, we surmise the child has come up with one or more rules to enable him/her to acquire the more complex form.

The focus seems to be predominantly on the lexical and syntactical forms. Semantics seemed to be mentioned but not much of a concern here. Behaviorists, on the other hand, tend to emphasize the function of speech (although not discounting the importance of syntax).

So, as a probably very naive example, consider a child who can say "Give me the apple". Pinker may have noted that the syntax is correct but omits the use of an adjective. Skinner may be wondering whether the child's statement will be reinforced by being given an apple. Now suppose at some later time there are two apples in sight, a red one and a green one. The child now says "Give me the red apple." Pinker has never heard the child use an adjective before and notes that as a development in language acquisition. Skinner wonders if the child's statement will be reinforced by being given the red apple and may be pleased to see that child was able to request that red one.

The child's syntax, for whatever reason, was correct but it happened in service of the child's request for an apple. It's wonderful he/she was able to say it in that way, but it also seems wonderful that he/she got an apple.