[1] Al-Tamimi, N. O. M., & Attamimi, R. A. (2014). Effectiveness of cooperative learning in enhancing speaking skills and attitudes towards learning English. International Journal of Linguistics, 6(4), 27-45. DOI: 10.5296/ijl.v6i4.6114.
[2] Arnab, R. (2017). Stratified Sampling. In R. Arnab (Ed.), Survey Sampling Theory and Applications (pp. 213– 256). Academic Press. DOI: 10.1016/B978-0-12- 811848-1.00007-8.
[3] Baker, J., & Westrup, H. (2003). Essential speaking skills. A&C Black.
[4] Braun, V., & Clarke, V. (2021). Thematic Analysis: A Practical Guide. SAGE.
[5] Brown H. D. & Lee H. (2015). Teaching by principles: An interactive approach to language pedagogy (4th ed.). Pearson Education.
[6] Brown, H. D. (2004). Language assessment: Principles and classroom practices. Longman
[7] Burns, A. (1998). Teaching speaking. Annual Review of Applied Linguistics, (18), 102–123. DOI: 10.1017/ S0267190500003500.
[8] Cahyani, F. (2018). The use of the Think-Pair-Share technique to improve students’ speaking performance. Research in English and Education Journal, 3(1), 76- 90.
[9] Chand, G. B. (2021). Challenges faced by bachelorlevel students while speaking English. IJELTAL (Indonesian Journal of English Language Teaching and Applied Linguistics), 6(1), 45-60. DOI: 10.21093/ ijeltal.v6i1.853.
[10] Cohen, L., & Manion, L. (1994) Research Methods in Education (4th ed.). London: Routledge.
[11] Cohen, L., Manion, L., & Morrison, K. (2000). Research Methods in Education (5th ed.). Routledge. DOI: 10.4324/9780203224342.
[12] Goh C. C. M. & Burns A. (2012). Teaching speaking: A holistic approach. Cambridge University Press.
[13] Harris, D. P. (1969). Testing English as a second language. McGraw-Hill Book Co.
[14] Hayes, A. How stratified random sampling works, with examples. (2022). Investopedia. Retrieved October 2, 2022, from https://www.investopedia.com/terms/ stratified_random_sampling.asp
[15] Heriansyah, H. (2012). Speaking problems faced by the English department students of Syiah Kuala University. Lingua Didaktika: Jurnal Bahasa Dan Pembelajaran Bahasa, 6, 37-40. DOI: 10.24036/ ld.v6i1.7398
[16] Hong, Y., Chen, L.-G., Huang, J.-H., Tsai, Y.-Y., & Chang, T.-Y. (2022). The impact of cooperative learning method on the oral proficiency of learners of the training program for English tourist guides. Frontiers in Psychology, 13, 866863. DOI: 10.3389/ fpsyg.2022.866863.
[17] Islam, W., Ahmad, S., & Islam, M. D. (2022). Investigating the problems faced by the university EFL learners in speaking the English language. International Journal of TESOL & Education, 2(2)47-65. DOI: 10.54855/ ijte.22223.
[18] Jain, V. (2014). 3D model of attitude. International Journal of Advanced Research in Management and Social Sciences. Retrieved June 10, 2023, from https://www.semanticscholar.org/ paper/3D-MODEL-OF-ATTITUDE-Jain/ eacc4246adf9ec72740f0b2dadff7c12f48e786c
[19] Johnson, D. W., Johnson, R. T., & Holubec, E. J. (1984). Circles of learning: Cooperation in the classroom. Interaction Book Company.
[20] Kemmis, S. and McTaggart, R. (1988). The Action Research Planner. Deakin University Press.
[21] Macpherson, A. (2007). Cooperative learning group activities for college courses: A guide for instructors. Kwantlen University College.
[22] Muhria, L. (2021). Using cooperative learning modelsnowball throw to improve students English learning outcomes. ELT Echo: The Journal of English Language Teaching in Foreign Language Context, 6(2), 224–234. DOI: 10.24235/eltecho.v6i2.9226.
[23] Mustafa, H. (2019). Using peer mediation and cooperative learning techniques to promote active learning and assess student learning outcomes in computer engineering classes. ASEE Annual Conference & Exposition, 2019.
[24] Mutlu, A. (2018). Comparison of two different techniques of cooperative learning approach: Undergraduates’ conceptual understanding in the context of hormone biochemistry. Biochemistry and Molecular Biology Education, 46(2), 114–120. DOI: 10.1002/bmb.21097.
[25] Namaziandost, E., Homayouni, M., & Rahmani, P. (2020). The impact of cooperative learning approach on the development of EFL learners’ speaking fluency. Cogent Arts & Humanities, 7(1), 1780811. DOI: 10.1080/23311983.2020.1780811.
[26] Nguyen, T. T., & Nguyen, T. M. L. (2020). Impact of cooperative Learning on speaking Competence of 10th-grade Students in Pho Yen high school. TNU Journal of Science and Technology, 225(12), 107-114.
[27] Nunan, D. (2003). Practical English language teaching. McGraw-Hill Education.
[28] Pham, T. N. (2020). Applying Kagan cooperative learning structures to improve 11th-grade students’ speaking skills at a high school in Thai Binh. Retrieved June 10, 2023, from http://repository.vnu.edu.vn/handle/ VNU_123/100320.
[29] Phan, H., & Do, T. M. L. (2021). Using the Think-PairShare strategy to support students in speaking lessons. Journal of English Language Teaching and Applied Linguistics, 3(4), 1-8. DOI: 10.32996/ jeltal.2021.3.4.1
[30] Qian, J. (2010). Sampling. In P. Peterson, E. Baker, & B. McGaw (Eds.), International Encyclopedia of Education (Third Edition) (pp. 390–395). Elsevier. DOI: 10.1016/B978-0-08-044894-7.01361-0.
[31] Raba, A. A. A. (2017). The influence of Think-Pair-Share (TPS) on improving students’ oral communication skills in EFL classrooms. Creative Education, 8(1), 12-23. DOI: 10.4236/ce.2017.81002.
[32] Renandya, W. A., Nguyen, T. T. M., & Jacobs, G. M. (2023). Learning to unlearn faulty beliefs and practices in English language teaching. Studies in English Language and Education, 10(1), 1-15. DOI: 10.24815/siele.v10i1.26009.
[33] Rides, S. (2017). The effects of cooperative learning teaching strategies on the speaking confidence and attitudes. ELT-Lectura, 4(2), 51-59. DOI: 10.31849/ elt-lectura.v4i2.2059.
[34] Riger, S., & Sigurvinsdottir, R. (2015). Thematic Analysis. In L. A. Jason & D. S. Glenwick (Eds.), Handbook of Methodological Approaches to Community-Based Research: Qualitative, Quantitative, and Mixed Methods 33-42. Oxford University Press. DOI: 10.1093/med:psych/9780190243654.003.0004
[35] Swaran Singh, C. (2020). The use of Think-PairShare of cooperative learning to improve weak students’ speaking ability. International Journal of Psychosocial Rehabilitation, 24, 4008–4023. DOI: 10.37200/IJPR/V24I5/PR2020111.
[36] Tran, T. T. D. (2020). Application of Cooperative Learning strategies to improve speaking skills for non-English major students in a police training institution in Vietnam. Retrieved June 10, 2023, from http:// repository.vnu.edu.vn/handle/VNU_123/108847.
[37] Van den Berg, H., Manstead, A., Van der Pligt, J., & Wigboldus, D. (2006). The impact of affective and cognitive focus on attitude formation. Journal of Experimental Social Psychology, 42, 373–379.
[38] Vanderkevent (1990). Teaching speaking and components of speaking. New York: Cambridge University Press.
[39] Vu, D. B., Ly, M. H., & Hoang, T. H. H. (2018). Using group-work activities to improve English speaking skills for the first-year English majors at Thai Nguyen University of Education. Journal of Science and Technology, 179(3), 97-102