Maturational Stages in the Development of Communication Systems By the Child. San Jose State Occasional Papers in Linguistics, Vol. 1, November 1975.

The prelinguistic child's attempts at communication cannot be viewed as rudimentary language. More than cataloguing overt acts, we need to understand the functional character of both language and non-language communication capabilities, and in particular the maturational stages of the internal communication systems that produce overt behavior in human beings. To describe the child's behavior without considering the nature and organization of the neural systems that produce the behavior is unreasonable. Above all, it must be realized that the child's observable behavior is only the tip of a neuropsychological iceberg. The conclusion that developmental stages are mere theoretical constructs, abstractions from a process that is actually continuous in nature, could only result from ignoring this fact. The forebrain limbic systems that became elaborated in primates constitute the primary level of human communication. The second arises at about 12 months in the form of neocortically based conceptual systems, including gestural behavior encoding components of propositional elements such as agent, patient, dative, etc., until recently largely ignored by psycholinguists. Only from about 20 months does the child use syntactical and morphological indicators to systematically encode components of the underlying conceptual message, and only at this point can the acquisition of a language system be said to have begun. (Author/AM)