The effect of conversational functioning on early language acquisition and use requires thorough developmental and discursive approaches able to take into account children's behaviors that present some but not necessarily all of the characteristics of the mature competence under study, and to preserve the "sequentiality" of conversation.
Results of a longitudinal study show that conversational functioning has the effect of furthering on topic conversation by both the mother and the child. Moreover, when the child produces a third turn contribution to reciprocal sequences, she is much more likely to modify her production than if she were repeating her preceding production without the mother's corrective uptake in between the two successive utterances.
These immediate effects of conversation have also longer-term effects. On the one hand, productions involved in exchanges at earlier sessions are recognized, at later sessions, as the words to which they have been linked to. On the other, reciprocal sequences are related to faster lexical acquisition.
Moreover, discursive exchanges in which children are led, through the unfolding of conversation, to successively utter words that can be meaningfully related one to the other, precede and foster multiword speech. All these kinds of conversational sequences create events that the partners may have not foreseen beforehand and it is such "unforeseen" novelties that constitute the crucial original contribution of conversations to early language progress.