The 1-year longitudinal study presented here examined the extent to which the ability to build phonologically specific lexical entries as a result of increasing vocabulary size predicts word reading via its impact on phonological awareness within and across languages in 62 emerging English (L1) and French (L2) Grade 1 children (M = 75.69 months, SD = 3.18) enrolled in an early French immersion program in Canada. Lexical specificity was assessed with a computerized word learning game in which children were taught new English (e.g., 'foal' and 'sole') and French (e.g., "bac" 'bin' and "bague" 'ring') word pairs contrasted by minimal phonological differences. The results revealed that the specificity of English words at the beginning of Grade 1 predicted English word reading at the end of Grade 1 and that this relationship was mediated by English phonological awareness at the beginning of Grade 1. French lexical specificity at the beginning of Grade 1 did not predict French word reading at the end of Grade 1. Notably, English lexical specificity at the beginning of Grade 1 also predicted French word reading at the end of Grade 1 and this relationship was mediated by English phonological awareness at the beginning of Grade 1. It is concluded that exposure to word pairs involving minimal phonological contrasts fosters phonological awareness, which in turn facilitates word reading within the L1 that then transfers to the L2.