The present study investigated the effect of computer- and mobile-mediated shadowing on Iranian impulsive and reflective English as a Foreign Language (EFL) learners' speaking ability. To collect the data, 100 intermediate participants, whose proficiency level was measured by administering Oxford Quick Placement Test (OQPT), took the pretest of speaking. A personality type questionnaire was also used to detect the learners' impulsivity or reflectivity. There were four experimental groups including 1) computer (Prezi) + shadowing + impulsive learners; 2) computer (Prezi) + shadowing + reflective learners; 3) mobile (WhatsApp) + shadowing +impulsive learners; and 4) mobile (WhatsApp) + shadowing + reflective learners. Then, the posttest was administered. After the descriptive and inferential analyses of the pre- and posttests, significant improvement was observed among the four experimental groups' speaking ability. However, reflective learners were shown to outperform the impulsive learners in both computer and mobile-mediated shadowing groups. The results can be beneficial to English language learners, teachers, teacher trainers, as well as material developers.