This paper examines article use in the L2-English of adult and child speakers of Russian, an article-less language. In earlier work on articles in adult L2-English, Ionin, Ko and Wexler (2004) proposed that speakers of article-less L1s fluctuate between dividing English articles on the basis of definiteness vs. specificity, as a result of direct access to semantic universals. The present paper examines whether similar fluctuation is present for child L2-English learners. Results of an elicitation study with L1-Russian child and adult learners of English show that both groups of learners exhibit sensitivity to definiteness as well as specificity. At the same time, it is found that the behavior of child L2-learners is more consistent with natural language data than that of adult L2-learners. It is proposed that both children and adults have domain-specific knowledge of semantic universals, but that adults, unlike children, also use explicit strategies. This proposal is considered in light of the literature on explicit vs. implicit knowledge.