Simanjuntak KV, Damanik BAR. THE EFFECT OF USING MOTHER TONGUE ON THE DEVELOPMENT OF COGNITIVE ABILITIES AND SECOND LANGUAGE IN EARLY CHILDHOOD. Sindoro [Internet]. 2024 Dec. 7 [cited 2025 Jul. 5];8(11):1-10. Available from: https://ejournal.warunayama.org/index.php/sindorocendikiapendidikan/article/view/7547