Language mixing in a given class is often avoided in bilingual education because of the generally held belief that one subject should be taught in only one language and one person should stick to one language in order to minimize confusion. Here, we compared the effects of mixing two languages and monolingual functioning on memory performance in immediate recall as a proxy for comprehension and attention during learning. In Experiment 1, non-balanced bilingual youngsters were provided with definition pairs introducing familiar objects in a single-language or in a mixed-language context. After each definition block, participants were asked to identify previously introduced objects presented amongst a stream of Old and New items. In Experiment 2, the same speaker produced the two definitions in the mixed-language context, thus violating the second principle introduced above In both experiments we found no advantage for the single-language over the mixed-language context of exposure.