It is an unofficial but widely spoken language in Ukraine, Moldova, Latvia and Estonia and, to a lesser extent, the other countries that were once constituent republics of the USSR.
It is the most geographically widespread language of Eurasia, the most widely spoken of the Slavic languages, and the largest native language in Europe.
Russian belongs to the family of Indo-European languages and is one of three (or four including Rusyn) living members of the East Slavic languages. Written examples of Old East Slavonic are attested from the 10th century onwards. The language is one of the six official languages of the United Nations.