This study investigated Spanish-speaking learners' awareness of a non-distinctive phonetic difference between Spanish and English through a delayed mimicry paradigm. We assessed learners' speech production accuracy through voice onset time (VOT) duration measures in word-initial pre-vocalic /p t k/ in Spanish and English words, and in Spanish words produced with an English accent. In addition, the second language (L2) English words and the English-accented Spanish words were rated, respectively, by first language (L1) English and L1 Spanish listeners on 9-point accentedness scales. Spanish-speaking learners were found to modify their native short-lag laryngeal timing patterns significantly, producing longer VOT durations in L2 English and, crucially, in their production of English-accented Spanish words, than they did in the production of L1 Spanish words. This was taken as evidence of learners having developed tacit phonological awareness of the cross-language VOT difference between Spanish and English voiceless stops.