Learning and cognitive ability are necessarily connected. Learning occurs when people engage in a series of cognitive processes. In this study, we examined how English as a foreign language (EFL) learners' cognitive abilities diffuse (i.e., change) effectively from a basic level (i.e., Remember, Understand) to a more advanced level (i.e., Apply) with the assistance of a peer-tutoring strategy that pairs high-achieving students with lower achieving students and asks them to use the mobile application, ezTranslate, in a familiar, authentic context. The results showed that the experimental students (i.e., the students who received peer tutoring) significantly outperformed the control students (i.e., the students who worked individually) on the posttest. Furthermore, throughout the learning activity, the majority of the experimental students' cognitive abilities transitioned from a basic to a higher level. Given these results, we suggested that peer tutoring is particularly advantageous because it helps students engage in high-level cognitive learning. By including mobile technology support with peer tutoring, teachers can utilize their students' differing abilities to promote collaborative learning, which results in not only successful learning but also encourages positive social interaction and results in high-level cognitive learning.