Abstract
This study assessed the letter-sound correspondence skills of kindergarten learners at Garchitorena Central School (SY 2024-2025). Specifically, it examined learners’ skills before and after using the busy book, evaluated the design and curricular validity of the developed intervention, and measured its effectiveness in improving the letter-sound correspondence skills of the kindergarten learners. A descriptive-comparative quasi-experimental research and development research method was employed. Data were collected using the adapted ELA Form 1 and evaluation checklists and analyzed using dependent samples t-test, mean, proficiency levels, and Cohen’s d for effect size. Results showed that initially, learners’ letter name and letter sound skills were at low levels, with mean scores of 6.40 and 5.61, respectively, categorized as Did Not Meet Expectations. Meanwhile, the phonemic busy book’s design received high validity ratings across learning objectives, content, activities, and assessment, with an average weighted mean of 4.94, which corresponded to a highly valid interpretation. Curricular validity of the Busy Book was also rated as highly valid, with an average weighted mean of 3.987. Then, after using the phonemic busy book, learners’ performance in letter name and letter sound improved significantly (p = 0.00) with a large effect size (Cohen’s d > 5.9), with mean scores of 19.40 and 18.93, respectively, categorized as Outstanding. Thus, the phonemic busy book was highly valid both in design and curricular validity and was effective in enhancing kindergarten learners’ letter-sound correspondence skills.