This document discusses the importance of a child's mother tongue in their development and future learning abilities. It argues that a child's first language, which they learn from birth from their mother, creates the powerful basis for their future life and learning. It provides several reasons for this, including that the mother tongue is essential for transmitting culture and developing a sense of identity and belonging. It also discusses that being proficient in one's mother tongue helps facilitate learning additional languages later on in life. The document recommends several techniques for promoting the use and development of a child's mother tongue at home.