In an increasingly globalized world mastering a second language (L2) provides a clear advantage. However, after early childhood, not everyone can easily learn a foreign language. The present study explored whether the large variability found in L2 attainment in the normal population, not diagnosed as learning disabled, is related to preattentive speech perception abilities. Using event-related potentials (ERPs) we examined the mismatch negativity, P3a, and the late discriminative negativity (MMN-P3a-LDN) complex, which served as an index for preattentive foreign phonological contrast discrimination abilities. Our results show that, compared to unsuccessful L2 learners, successful L2 learners had shorter latencies of the MMN and P3a components and higher amplitudes of the LDN component. These results suggest that unsuccessful L2 learners have a deficient speech perception mechanism.