Aims: Previous research showed that short-term second language training modulates children’s brain responses. However, little is known about how well young children’s brains process second language-related information acquired from short-term usage of language-immersive apps. Methodology: To examine this, we compared the auditory event-related potential (ERP) to non-native language words learnt via language-immersive applications (apps), as compared to those learnt via digital flash cards, in 3-5-year-old children. We also compared their auditory ERPs to known and unknown words. Data analysis: Thirty-two participants have completed the (audio) word-picture pair experiment while their electroencephalography (EEG) was recorded. We compared the auditory ERPs in the 200-300ms window and the 400-600ms window between the apps group and the flash-card group, and the response to the known and unknown words. Results: We found that the early positive potential (of the whole group) to the known words was significantly larger than that to the unknown words. Further, the early negative potential of the language immersed group was significantly larger than that of the flash card group. Conclusions: Short-term training from language-immersive apps has a positive impact on the developing brain.