February 21 is International Mother Language Day, established by UNESCO in 1999, "to promote the preservation and protection of all languages used by peoples of the world".
International Mother Language Day is an observance held annually on 21 February worldwide to promote awareness of linguistic and cultural diversity and multilingualism. It was first announced by UNESCO on 17 November 1999. Its observance was also formally recognized by the United Nations General Assembly in its resolution establishing 2008 as the International Year of Languages.
The United Nations Educational, Scientific and Cultural Organization (UNESCO) had adopted February 21 as International Mother Tongue Language Day to commemorate the Bengali language movement which witnessed five students of University of Dhaka being killed in a protest against the imposition of Urdu as the sole national language policy on February 21, 1952.
According to UNESCO there are some 6,000 languages in the world, half of them are so rarely used that may cease to exist if not protected and cultivated.