Development and Validation of Supplemental Reading Materials for Filipino 9

This study aimed to develop and validate supplemental localized reading materials in Filipino 9 to address the literacy gaps of Grade 9 students at the "Frustration Level" in Margarito A. Duavit Integrated School. Utilizing a Research and Development (R&D) design following the 4D Model (Define, Design, Develop, Disseminate), the researcher identified ten (10) Least Mastered Learning Competencies (LMLC) in Literary Analysis, Vocabulary, and Grammar. The developed materials integrated the local heritage and narratives of Pilapila, Binangonan, Rizal, providing "cultural scaffolding" to reduce cognitive load. Rather than testing student impact, the study focused on establishing the technical quality and pedagogical soundness of the materials. Results from expert validation revealed a Grand Mean of 4.97 (Very Highly Valid) and a Grand Mean of 4.89 (Very Highly Acceptable) for classroom utility. The study achieved a perfect Content Validity Index (CVI) of 1.00, confirming unanimous expert consensus on the materials' integrity. These findings certify the worktext as a technically sound and instructionally ready tool for addressing reading frustration.