This study tested the predictions of the Revised Hierarchical Model (RHM) proposed by Kroll and Stewart (1994) and a subsequent model proposed by La Heij et al. (1996). The RHM claims that; a) backward translation is faster than forward translation b) forward translation is conceptually mediated whereas forward translation is less conceptually mediated c) as proficiency increases, conceptual links map L2 lexicon to concept develops. La Heij et al (1996) claim that backward and forward translation is conceptually mediated regardless learners’ proficiency level and the time it takes to translate from L1 to L2 (forward translation) and from L2 to L1 (backward translation) is almost identical. To test the predictions of the two models, we tested the performance of less and more proficient bilinguals on a bilingual translation task and observed the effect of nonverbal semantic contexts on the translation performance. The logic of the study is that if backward translation is conceptually mediated, then we would expect to find nonverbal context effect on the performance of the two groups of participants. If, however, backward translation is lexically mediated then it should not be affected by the existence of nonverbal context. Results showed that forward translation was faster than backward translation. The magnitude of semantic context effect did not differ for backward translation and forward translation. Backward translation and forward translation were conceptually mediated regardless subjects’ proficiency level. We considered the implication of these findings as evidence in support of the model proposed by La Heij et al. (1996).