When is International Mother Language Day, recognized by the UN World Tourist Guide Day and International Mother Language Day originated as the international recognition of Language Movement Day, which has been commemorated in Bangladesh since 1952, when a number of Dhaka university students were killed by the Pakistan police and army in Dhaka during the Bengali Language Movement observed?

The correct answer is: 21 February.

International Mother Language Day is observed on 21 February every year. It was proclaimed by UNESCO in 1999 to promote linguistic and cultural diversity and multilingualism. The day is observed to commemorate the Bengali Language Movement, which took place in Bangladesh in 1952. The movement was a protest against the Pakistani government’s decision to make Urdu the sole national language of Pakistan. The movement resulted in the deaths of many Bengali language activists, and is considered to be one of the most important events in the history of Bangladesh.

The other options are incorrect because they are not the dates of International Mother Language Day. 11 December is World AIDS Day, 12 August is International Youth Day, and 14 November is World Diabetes Day.