Yulianti Purwaningsih; Supadi Supadi; Amrina Rosada
This study aims to evaluate the effect of Mastery of Parts of Speech on students' Writing skills in Descriptive Text English at the High School Education level at SMA Pangudi Rahayu Class XI Jakarta. This research method uses a qualitative approach with in-depth interviews with students and teachers, as well as document analysis of students' descriptive writing assignments. Direct observation in the classroom is also carried out to understand the application of Mastery of Parts of Speech in the teaching and learning process. Data were collected from a variety of sources and analyzed thematically to identify patterns and relationships between grammar mastery and writing skills. The results show that a strong understanding of Mastery of Parts of Speech significantly improves the quality of students' Descriptive Text English. The contribution of this research lies in the provision of teaching strategies based on grammar mastery to improve descriptive writing skills at the secondary education level.