Bengali () or Bangla (; ) is the language native to the region of Bengal, which comprises the present-day nation of Bangladesh and of the Indian states West Bengal, Tripura and southern Assam. It is written using the Bengali alphabet. With about 220 million native and about 300 million total speakers, Bengali is one of the most spoken languages, ranked fifth in the world. The importance of this language to the countries of South Asia can be noted by the fact that the National Anthem of Bangladesh, National Anthem of India, National Anthem of Sri Lanka and the national song of India were all first composed in the Bengali language. Standard Bengali in Bangladesh and West Bengal are marked by some differences in usage, accent, and phonetics. Today, literary form and different dialects of Bengali constitute the primary language spoken in Bangladesh, and the second most commonly spoken language in India. With a rich literary tradition arising from the Bengali renaissance, the Bengali language binds together a culturally diverse region and is an important contributor to Bengali nationalism. The Bengali Language Movement ( Bhasha Andolôn) was a movement in 1951–52 in what was then East Pakistan (today Bangladesh) that heavily linked Bengali identity with the Bengali language. On 21 February 1952, protesting students and activists sacrificed their lives at the Dhaka University campus for the right to read, write, and speak in their mother language of Bengali. In 1999, UNESCO declared February 21 as International Mother Language Day in recognition of the people who sacrificed their lives for their right to use the Bengali language, instead of the then-state imposed Urdu language.