Drawing on qualitative research, this study explored, from a complex dynamic systems theory perspective, the motivation of Burundi junior high school students simultaneously learning L2 French, L3s English and Kiswahili. It aimed to fill the gap in research on (1) changes in motivational dynamics and factors responsible for any fluctuations in the levels of motivation over time and (2) complex interactions between different learner variables among multiple language learners. Twelve school pupils who were all Kirundi native speakers participated in this study. Retrospective interviews were used to collect data relating to the students’ multilingual learning experiences over the period of their formal education. The findings indicated that the intensity of learning each target language fluctuated over time, with English generally enjoying the highest increase and Kiswahili the lowest and that different factors were responsible for such dynamic changes. Besides, complex interactions between the students’ L1, L2, and L3s linguistic knowledge and their foreign language learning motivations were revealed. These results indeed highlight the complex and dynamic nature of motivation in learning multiple languages. In light of these findings, practical implications are discussed based on the Burundi educational context.
