Used growth curves and dynamic-systems modeling to examine early lexical and grammatical development of one male child. Found that lexical development described a pattern of logistic growth. Plural growth began after reaching a threshold in vocabulary size. Lexical growth slowed as plural growth increased, and increased when plural use reached…

Examined 1 hour of conversation between 12 mothers and their 23-month-old children. Children were more likely to imitate correct grammatical morphemes after mothers' corrective recasting of children's errors than after three types of maternal responses that did not correct an error but did model a morpheme. (BC)