Experimental studies demonstrate that contrast helps toddlers to extend the meanings of novel adjectives. This study explores whether antonym co-occurrence in spontaneous speech also has an effect on adjective use by the child. The authors studied adjective production in longitudinal speech samples from 16 children (16-36 months) acquiring eight different languages. Adjectives in child speech and child-directed speech were coded as either unrelated or related to a contrastive term in the preceding context. Results show large differences between children in the growth of adjective production. These differences are strongly related to contrast use. High contrast users not only increase adjective use earlier, but also reach a stable level of adjective production in the investigated period. Average or low contrast users increase their adjective production more slowly and do not reach a plateau in the period covered by this study. Initially there is a strong relation between contrast use in child speech and child-directed speech, but this relation diminishes with age.