Mobile language learning (MLL) is an emerging field of research, and many MLL applications have been developed over the years. In this paper, a systematic literature review (SLR) was conducted to establish a body of knowledge on the development of MLL applications. The SLR analyzed forty seven papers from seven different digital libraries reporting on the development of MLL applications. The objective was to consolidate information on; (i) requirements elicitation, (ii) design and implementation, and (iii) evaluation processes. The results highlighted literature reviews and interviews as the main source for gathering requirements, while app development technologies, speech technology, and gamification technology are widely used in the design and implementation process. Usability testing is the most commonly used evaluation method. Finally, future work is recommended to scientifically strengthen the field.