June 6 is UN Russian Language Day. It coincides with the birthday of Aleksandr Pushkin, the father of modern Russian literature.
The initiative of the UN Language Days was launched in February 2010 in order to celebrate multilingualism and cultural diversity and to promote equal use of all six of the UN’s official working languages throughout the organization.
The other languages and days are:
Chinese, April 20 in commemoration of Cangjie, inventor of Chinese characters in 2000 B.C.
Arabic, December 18 commemorating the day in 1973 when Arabic was approved as one of the United Nations’s Official Languages.
French, March 20, the anniversary of the formation of the International Organization of La Francophonie.
English and Spanish are both celebrated on April 23, as it is the birthday of both Shakespeare and Cervantes.
International Mother Language Day is February 21 honoring the Bangladeshis martyrs who fought for recognition for the Bangla language.

This portrait of A. S. Pushkin was realized by Orest Kiprensky, 1827. The original hangs in Tretyakov Gallery in Moscow.