Experiencing anxiety is a major obstacle for language learners, especially in productive skills. Among these, speaking is considered to be generally the most challenging. Clearly, many students are affected by Foreign Language Speaking Anxiety (FLSA) and this negatively affects many aspects of their language learning experience, such as group work, speaking tests, presentations etc. Although many studies examine the causes of students' FLSA, there is a lack of focus on individual-specific causes. This qualitative multiple case study aimed to examine the phenomenon of FLSA, and explore the root causes of this problem, aiming at providing teachers with specific solutions to enable them to develop more effective ways to assist their students. Three preparatory class students participated in this study. The data was collected through the participants' diaries, semi-structured interviews and the researcher's informal participant observation over 6 weeks. The findings revealed that the causes of FLSA are highly personal and therefore, generally unpredictable. While certain causes have received much attention, others are practically invisible to teachers and therefore difficult to deal with effectively. The results emphasize the need for teachers to fully consult students before deciding on approaches to overcome FLSA. [This paper was published in: "EJER Congress 2023 International Eurasian Educational Research Congress Conference Proceedings," Ani Publishing, 2023, pp. 322-336.]