This paper reports a transition from affective to linguistic meaning in 15-month-old infants. Behaviour regulation in the context of a social referencing procedure is used as a measure of the meaning of stimulus messages for infants. Of particular interest is the extent to which receptive vocabulary predicts behaviour regulation by language and paralanguage. Approving and disapproving lexical content was completely crossed with approving and disapproving facial and vocal paralanguage to produce stimulus messages. At the group level, the behaviour of 15-month-olds was better regulated by paralanguage than by lexical content. However, receptive vocabulary was a significant predictor of the relative primacy of language and paralanguage: infants who understood the lexical content of stimulus messages were better regulated by lexical content than by paralanguage. These data suggest a transition from affective to linguistic meaning in comprehension that parallels the transition from affective expression to expression that integrates affect and language.