What motivates people to learn a language other than English (LOTE) in addition to English? As distinct as the motivational systems to learn different languages might be, they can also be understood as different interconnected subsystems embedded in a larger system. Previous studies have argued that such motivational systems may be in constant interaction with each other, in co-adaption to the learning context, and lead to the emergence of an ideal multilingual self system. Following this argumentation, the current study examines the emergence of a multilingual motivational system among Chinese learners. English + LOTE (E-LOTE) learners were compared to English-only learners to uncover the special attributes in E-LOTE learners' motivations; then the relationship between the E-LOTE learners' motivation to learn English and to learn the LOTE was investigated. The results demonstrated that E-LOTE learners had a higher interest in English than the English-only learners and had established a more salient ideal English self. Moreover, the E-LOTE learners’ motivation to learn the two languages interacted with each other over time. These results confirm the hypothesis that a multilingual motivational system emerges from the self-organization of the learner system and the co-adaption to the context.