Based on the Technology-Based Learning Model, the present study reviewed open online language learning research published in the Scopus database from 2009 to 2018, with a focus on research design, sample size, learning devices, target languages, language skills, the learners' education level, the learners' language proficiency level, learning methods, and the foci of investigation. In terms of research design, quantitative empirical studies accounted for the most, followed by mixed method studies. As for the target languages, English was investigated the most, with few studies focused on other languages. In terms of language skills, the number of studies related to vocabulary and speaking was less than those concerning reading and writing. With regard to learning methods, self-directed learning, blended learning, and peer review were the most commonly adopted. There was little research on collaborative learning, flipped classrooms, adaptive learning, or thematic-oriented learning. As for the foci of investigation, motivation, interest, and satisfaction were the focus of the majority of the studies. On the other hand, little research was found to examine self-efficacy or confidence. A discussion based on the analytic results is presented along with proposed suggestions for future research directions.