Native language background exerts constraints on the individual's brain automatic response while learning a second language. It remains unclear, however, whether second language immersion experience could help the brain overcome such constraints and meet the requirements of a second language. This study compared native Chinese speakers with English-as-a-second-language immersion experience (immersive English learners), native Chinese speakers without English-as-a-second-language immersion experience (nonimmersive English learners), and native English speakers with an ERP cross-modal MMN paradigm. The results found that English-as-a-second-language immersion could benefit speech perception for native Chinese speakers. In addition, both immersive English learners and native English speakers showed enhanced cross-modal MMN, indicating that second language immersion could help native Chinese speakers successfully integrate English letter–sound like native English speakers. The present study further revealed that English listening and speaking exposure in an immersive environment is important in English letter–sound integration for immersive English learners.