International Mother Language Day

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.

Well in Bangladesh Mother Language Day or Language Martyrs day is the most widely observed occasions of all.

In 21 February 1952 people of Bangladesh (East Pakistan at that time) died to establish the right to use their Mother Language as state language. Later through many events these protests evolved into a want for freedom and in 1972 through the liberation war Bangladesh (East Pakistan at that time) gained independence from Pakistan. So this day is observed as a symbol of fight for rights in Bangladesh. Fairs, Book Fairs, Concerts, Rallies etc are organized throughout February to commemorate the sacrifice of Language Martyrs of 1952.

International Mother Language Day has been observed every year since 2000 February to promote linguistic and cultural diversity and multilingualism. The date represents the day in 1952 when students demonstrating for recognition of their language, Bengali, as one of the two national languages of the then Pakistan, were shot and killed by police in Dhaka, the capital of what is now Bangladesh.

International Mother Language Day was proclaimed by the General Conference of the United Nations Educational, Scientific and Cultural Organization (UNESCO) in November 1999 (30C/62).On 16 May 2009 the United Nations General Assembly in its resolution A/RES/61/266 called upon Member States "to promote the preservation and protection of all languages used by peoples of the world". By the same resolution, the General Assembly proclaimed 2008 as the International Year of Languages, to promote unity in diversity and international understanding, through multilingualism and multiculturalism.
Languages are the most powerful instruments of preserving and developing our tangible and intangible heritage. All moves to promote the dissemination of mother tongues will serve not only to encourage linguistic diversity and multilingual education but also to develop fuller awareness of linguistic and cultural traditions throughout the world and to inspire solidarity based on understanding, tolerance and dialogue.
—from the United Nations International Mother Language Day microsite