tend to provoke others into asserting their needs or plans. Some of the children's utterances will be met with statements that are sharply contrastive; some of the children's utterances will be met with questions; still others of the children's utterances may be met by commands, or comments, or even silence. There is thus strong pressure on children to learn to select utterances that produce desirable effects. This aspect of the populated environment is why learning about points of view is not just learning a new fact but a fundamental cognitive milestone. The child is learning that the environment is populated with other active, motivated, planful observers and speakers. Indicational language thus contains the seeds of its own transcendence, because it sets in motion the forces that act to socialize the child's propensity to promote the actions of others. It is thus variations in needs and points of view that are key elements in structuring the child's linguistic environment in such a way as to provide information concerning the significance of varying speech structures and that set the child on the road to making discoveries about the generative patterns inherent in the language around him or her.
Note that nothing else but indicational language (whether speech or gesture is irrelevant) can act in this way to catalyze caretakers into beginning to engage in full- scale speech acts and conversational frames on a regular basis with children. Note also that nothing else but specific variations in the child's utterances is capable of causing major shifts in the kinds of effects generated by the child's speech (e.g., simple shifts of tone or terms used can cause succor to turn to anger, or friendly help into laughter). Because the child who has mastered indicational speech has already mastered the structure of interpersonal dialogue routines and has already begun to use at least some of the words in the language, he or she is poised on the border of the local linguistic community and will begin to be drawn in inevitably as the child monitors the consequences of his or her own actions.
The not quite 2-year-old child is in a most interesting situation. She has mastered dyadic interactions of considerable intricacy and now reliably uses scores, if not hundreds, of wordlike vocalizations to act on or to indicate aspects of these situations. But such an action system, as was emphasized above, is both inflexible and suffers from idiosyncrasy. Indicational language users can make themselves understood--up to a point, and only with a select group of listeners--and can bring about complex speech and action in their interlocutors. And, no doubt, these children understand considerably more than they produce. But what kind of mechanism could cause them to change from using words merely to indicate things into being capable of uttering genuine speech acts, containing propositional structures that are well formed according to the rules of the language?
The suggestion offered here is that it is the inherent instability of indicational language itself that constitutes a process for promoting the acquisition of generative language skills. This developmental transition is embodied in three kinds of conflict that motivate the child to resolve them: