This paper discusses the development of children's communicative abilities in relation to three models: the psycholinguistic model, which posits that grammatical competence is achieved through children's innate ability to abstract linguistic rules and apply them in creating sentences; the Bernstein hypothesis, which holds that not everyone acquires and maintains the same coding ability--social and other relationships influence communication; and the communication-based model, which considers the total environment of children to be input during language development. The paper concludes that, in exploring the functional development of children's communicative abilities, the communication-based model should be used to examine the stages through which children move to communicate both material needs and affective needs. (JM)