ABSTRACT
The child’s acquisition mechanism is termed a “rare event” mechanism because it is only rarely that the child successfully attends to new input and arrives at new structural descriptions that advance the language system and are used in processing further utterances from others and in producing new utterances by the child. Cognitive comparisons between old structures and new structures are crucial within each domain. As long as the new input string can be successfully matched to an old structural description the child will simply interpret the new input according to the old rules and structures. When the power of the comparison system is selectively focused on mismatches within particular foci of analysis, there are several levels of selective storage which take place for selected input strings. The chapter describes with the mechanisms of the child that lead to progress in language acquisition and also with the conditions which contribute to the child making successive advances in language acquisition.
