This mixed-methods study examined the effectiveness of Rosetta Stone, a mobile-based language learning application, on Chinese EFL students' listening, speaking, foreign language enjoyment (FLE), and foreign language anxiety (FLA). Two groups of intermediate Chinese EFL students from a language institute, with 33 students in the control group and 36 in the experimental group, were recruited as the participants. The treatment lasted for 3 months, with the experimental group using Rosetta Stone in addition to in-class instruction whereas the control group received only the regular in-class instruction. Data collection involved administering IELTS module tests of speaking and listening, FLE and FLA scales, as well as semi-structured interviews. ANCOVA, paired samples test, and content analysis were used for the data analysis of the quantitative and qualitative data. The results indicate that the experimental group showed significant improvements in their listening, speaking, FLE, and reduced FLA more than the control group. The results of the qualitative data indicated that the students had positive attitudes toward mobile-based language learning. The qualitative findings provided further support to the quantitative results and highlighted the convenience, flexibility, and engaging nature of the application. The outcomes stressed the potential benefits of using mobile-based language learning tools like Rosetta Stone as an effective supplementary method for improving EFL learning outcomes and promoting positive affective variables. This study looked at how a mobile language learning app called Rosetta Stone affected Chinese students' listening, speaking, enjoyment of learning a foreign language, and anxiety about learning a foreign language. The researchers had two groups of intermediate Chinese students: one group used Rosetta Stone along with regular classroom instruction, and the other group only had regular classroom instruction. The study lasted for 3 months. The researchers tested the students' listening and speaking skills, as well as their levels of enjoyment and anxiety in learning a foreign language. They also conducted interviews with the students. The results showed that the group using Rosetta Stone had significant improvements in listening, speaking, enjoyment, and reduced anxiety compared to the group that only had classroom instruction. The interviews supported these findings and showed that the students liked using the mobile app because it was convenient, flexible, and engaging. Overall, this study suggests that using mobile language learning apps like Rosetta Stone can be a helpful addition to regular classroom instruction, improving language learning outcomes and students' positive attitudes. However, it's important to note that this study had some limitations, such as the small sample size and focus on a specific language app, so further research is needed to confirm these findings in different contexts and with larger groups of students.