THE EFFECT OF GROUP INVESTIGATION METHOD TOWARDS STUDENTS SPEAKING COMPETENCE BASED ON STUDENTS SELF-CONFIDENCE AT SMAN 1 SAKRA TIMUR IN ACADEMIC YEAR 2017/2018. JISIP [Internet]. 2018 Nov. 13 [cited 2026 Jun. 23];2(3). Available from: https://ejournal.mandalanursa.org/index.php/JISIP/article/view/569