There is controversy in the literature on language acquisition concerning whether L2 learners develop separate systems for the two languages or they construct a unitary system for both (i.e. interlanguage). Here we investigate whether Voice Onset Time (VOT) can provide evidence supporting one of the two perspectives mentioned. To assess the research question, we asked 16 Turkish speakers of English to produce 30 words (both in Turkish and in English) starting with oral plosives in a prevocalic word-initial position. 8 native speakers of English also produced the same English words to provide us with English VOT norms. A comparison of mean VOT values revealed that Turkish speakers of English produce English /b, d, g/ with VOT values that are intermediate to the short-lag phonetic norm of English and the pre-voiced VOT norm of Turkish. We consider this an indication of the development of interlanguage VOT patterns.