This study investigated information management in Mandarin child speech, maternal speech, and adult speech. The three types of speech were analyzed to test the hypothesis of preferred argument structure (Du Bois, 1987 ; Du Bois, 2003), and they were also analyzed in terms of two types of discourse information measures. The data consisted of eight hours of mother–child (aged 2;2 to 3;1) conversation and one hour of adult–adult conversation. The analysis of the data showed that the three types of speech demonstrated similar patterns in grammatical alignment and that all of them followed the constraints of quantity. The discourse information measures, on the other hand, showed that the three types of speech differed significantly in the measure of information pressure and in the measure of lexical referential density. The results revealed how information management may be associated with children's developing linguistic ability, mothers’ speech adjustments, and adults’ mature competence.