I understand you got many references but I wonder if I could suggest some initiatives from your level. First, develop a conceptual model based upon your experience and literature. Then take help of these publications. After that finalise your model by integrating four language skills including the most important skill (thinking) and self-talk of these students. Hopefully, this will give you a good real baseline level to extend speaking proficiency of the students. Perhaps see Munby as well. I have some strategies for speaking, you may like to keep in touch. I can sort out something for you. Thanks!
Al-Saraj, T. M. (2011). Exploring Foreign Language Anxiety in Saudi Arabia: A Study of Female English as Foreign Language College Students (Unpublished doctoral dissertation). Institute of Education, University of London.
Al-Saraj, T. M. (2014). Revisiting the foreign language classroom anxiety scale (FLCAS): The anxiety of female English language learners in Saudi Arabia. L2 Journal, 6, 50-76.
Exploring the Factors of Classroom Anxiety in the Context of EFL Arab Students: