The language people learn from their mother is called mother language. people can express their feeling and emotion through it easily and freely. It is wholly, solely and vitally related to their lives and livelihood. So the importance of mother tongue is very great. the Pakistani rulers wanted to snatch away our mother tongue Bangla and tried to declare Urdu as the only state language. but our brave and valiant sons did not sustain the declaration and so they created a movement throughout the country. The police fired on our moving sons and as a result Salam, Rafique, Jabbar, barkat and many others were killed. At last, the the conspiring rulers were bound to accept our mother tongue. Today our mother tongue Bangla is recognized not only nationally but also internationally. From Canada Rafiqul Islam and Abdus Salam sent a memorandum to Kofi Anan on 9 February as International Mother Language Day. Kofi Anan advised them to make contact with UNESCO. Then Bangladesh officially sent a proposal to UNESCO on 9 September 1999. The proposal was accepted on 17 November 1999 and this 21 February got its status. The declaration made by UNESCO regarding the day was that it would be observed every year as International Mother Language Day. And the declaration was made to show respect to the supreme sacrifice of the language martyrs and also to save minor mother languages from extinction. Therefore, we should be committed to preserving the significance of the day at any cost.