The objectives of this study are to design PIKA (Pintar Kalimat Imbauan dan Ajakan, or Smart Sentences of Exhortation and Encouragement)-based teaching materials grounded in the discovery learning approach, to identify the appropriateness of the developed media, and to examine the responses of educators and students to its use. The novelty of the PIKA development lies not only in its form as a website-based learning medium but also in the integration of the discovery learning approach with a digital learning ecosystem that is interactive, adaptive, and oriented toward student engagement. PIKA is designed to transform learning activities—which previously tended to be centered on the delivery of content—into a learning experience that enables students to discover concepts, experiment, and test their understanding through educational games. Another unique feature lies in the integration of content, exploration activities, sentence-building games, drag-and-drop games, a two-player game mode, a scoring system, and visual and audio elements into a single, fully integrated learning page. This study adopted the Research and Development (R&D) method using the ADDIE framework, which encompasses the stages of Analysis, Design, Development, Implementation, and Evaluation. The study involved sixteen second-grade students from SDN Truneng. The data collection tools used included an interview guide for teachers, validation instruments by subject matter experts and media experts, and response questionnaires for teachers and students. Data acquisition was conducted through observations of learning activities, in-depth discussions with teachers regarding instructional needs and barriers, and the distribution of questionnaires to assess the acceptability of the media in terms of content, language, and visualization, accompanied by documentation to support the empirical data. All data were then analyzed using percentage-based descriptive analysis techniques. The study’s findings indicate that the developed media achieved a validity rate of 95.4%, classifying it as highly suitable. The content and linguistic aspects achieved a validity of 92.1%, indicating a very high level of appropriateness. The response rate from educators reached 91.6%, while that from students reached 97%, both falling into the “very good” category. In addition, the evaluation of learning implementation achieved a score of 90 percent. Based on these results, the PIKA-based teaching materials, combined with discovery learning, are highly effective for use as a tool to support Indonesian language learning at the elementary school level and have the potential to strengthen students’ motivation to learn.