Concept:Mother tongue based multilingualism uses the learner's first language as a foundation for learning additional languages.Explanation:Children start their formal education in their mother tongue or home language.Then they gradually add at least two more languages in school.This method supports cognitive development and reasoning skills.It ensures a smooth transition from home to school language.Multilingual children show better academic performance and creativity.Answer:Option A: learners begin their schooling in mother tongue and move on to add many more (at least two) languages in school.