Examined role of social-referential context in 13- and 18- month-olds' mapping of verbal and nonverbal symbols to object categories. Found that infants at both ages showed evidence of learning both words and sounds when the experimenter produced a label within a familiar naming routine, and failed to learn when labels were emitted from a baby monitor, suggesting that context, not the form per se, determined infants' symbol learning success. (Author/KB)