This study aims to achieve three primary objectives: firstly, to develop a competency-based program tailored for communication purposes; secondly, to examine developmental strides in language proficiency for effective communication; and thirdly, to compare the language proficiency among early primary school students, both preand post-implementation of the program. The sample consisted of third-grade students from Anuban Chantarat School, Sahatsakhan District, Kalasin Province, Thailand, who were enrolled in the second semester of the academic year 2022. The total number of participants was 20 by cluster random sampling. The data collection instruments used in this study were: 1) a program usage manual, 2) a lesson plan, and 3) a language communication competence assessment test. Data analysis involved basic statistical measures, including frequency, percentage, mean, standard deviation, and hypothesis testing using the t-test (Dependent Samples). The study findings revealed that: (1) Competency-based program for early primary school students' language communication, comprising six components: 1) Principles, 2) Objectives, 3) Content, 4) Development Processes, 5) Teaching and Learning Materials, and 6) Assessment, underwent quality assessment by seven experts. The results indicated a high level of conformity and appropriateness; (2) Students who participated in the language competency-based program demonstrated enhanced language communication competence across all learning units; (3) The language communication competence of students after using the program was statistically significantly higher than before using the program at a significance level of 0.05. The language competence was found to be at a developing level of A2 proficiency.