This study investigates the benefits of Mobile Mediated Communication (MMC) to develop oral skills in second-language learners. A total of 80 Spanish students taking a B1 English course at the University of Almería were studied in this research. According to treatment type, subjects were divided in two groups, experimental and control. A "Whatsapp" group was created where 40 of these students participated in a daily interaction during six months. The samples collected in the application as well as a speaking were used to measure the students' degree of oral development and the type and triggers of the language related episodes (LRE) given rise to mobile chat-based oral interaction. This study focuses on such interaction and seeks to measure the students' degree of oral development through a mixed analysis approach. A temporal axis is used to measure the differences between the groups studied. Significant improvements in term of oral proficiency were observed in the experimental group and negotiations were the LRE most common throughout the activity. it is worth mention that Mobile learning offers an environment where learners can ubiquitously negotiate meaning, reflect and evaluate on their own performance through authentic interaction and feedback, constituting a powerful tool for developing second language proficiency.