Patterns of mother and sibling object labeling were observed during play. Subjects were 40 Mexican-descent mothers, their children aged 2-3, and older siblings. Mothers provided names for objects (referential labeling) as often as they mentioned objects within the ongoing activity (labeling in action), while siblings more frequently used referential labeling. Results suggest diverse conversational motivations and normative scripts for object labeling. (Contains 65 references.) (Author/SV)