21 February was proclaimed the International Mother Language Day 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.
International Mother Language Day originated as the international recognition of Language Movement Day, which has been commemorated in Bangladesh (formerly East Pakistan) since 1952, when a number of Bangladeshi university students were killed by the East Pakistan police and army in Dhaka.
International Mother Language Day is observed yearly by UNESCO member states and at its headquarters to promote linguistic and cultural diversity and multilingualism.
On 21 February 1952, corresponding to 8 Falgun 1359 in the Bangla calendar, a number of students campaigning for the recognition of Bangla as one of the state languages of Pakistan were killed when police fired upon them. At a public meeting on 21 March 1948, Mohammed Ali Jinnah, the Governor general of Pakistan, declared that Urdu will be the only language for both West and East Pakistan. The people of East Pakistan (now Bangladesh), whose main language is Bengali, started to protest against this. A student meeting on 21 February called for a province-wide strike. But the government invoked Section 144 on 20 February. The student community at a meeting on the morning of 21 February agreed to continue with their protest but not to break the law of Section 144. Even then the police opened fire and killed the students.