International Mother Language Day is a worldwide annual observance held on 21 February to promote awareness of linguistic and cultural diversity and to promote multilingualism.

 On International Mother Language Day UNESCO and UN agencies participate in events that promote linguistic and cultural diversity. 

They also encourage people to maintain their knowledge of their mother language while learning and using more than one language. Governments and non-governmental organizations may use the day to announce policies to encourage language learning and support.

IMLD is a public holiday in Bangladesh, where it is also known as Shohid Dibôsh, or Shaheed Day. It is a global observance but not a public holiday in other parts of the world.

Source: - Youtube