In the second stage, the negative can be put within the utterance, between the subject and predicate, and may be attached to an auxiliary verb. Examples without auxiliaries include: "He no bite you," and "He not little." Examples with auxiliaries include: "I don't want it," "I can't see you." The auxiliary verbs occur only when accompanied by a negative, and do not appear in questions or declarative utterances at this stage. Therefore, "can't" and "don't" are considered to be lexical representations of negative verbs; for the child, they do not consist of two separable words. The child's negative utterances at this stage are generated by Klima and Bellugi by a simple phrase-structural grammar.

In the third stage, the auxiliaries begin to appear in declarative sentences and questions as well as in negatives. Therefore they are now considered as separate from the negative elements, and "can't", "don't", and so forth each consist of the combination of two words that are represented separately in the lexicon. That is, the child's rules have become reorganized-he has realized that the same auxiliaries can appear in various ways. The child's negative forms have also advanced in other ways and it is now necessary to incorporate transformational rules to generate them.

We have seen, then, that the child progresses from one-word utterances to simple, ordered utterances, consisting of two words that directly reflect the underlying conceptualization. He learns to modify the basic meanings by using function words and grammatical inflections. Then he begins to represent more complex conceptualizations and to use longer, more complex sentences. His knowledge both increases and becomes reorganized. Eventually, he acquires various ways of representing any conceptualization (e.g., agent-action-object can be represented by either a passive or an active sentence). His languaging abilities are now quite powerful-a great many things can be clearly expressed and fine distinctions and complex ideas can be communicated. However, the means of languaging are complex; there is a very indirect mapping of conceptualization to language and back again. A great deal of linguistic knowledge has been acquired. How this knowledge is acquired will be considered next.

The Processes of the Acquisition of Syntactic Knowledge. Those descriptions of the stages a child progresses through before acquiring adult language abilities do not provide any ideas of the processes underlying the acquisition of syntax. How does the child acquire knowledge of the rules for selecting and sequencing the signs of his language?