Russian is a Slavic language in the Indo-European family. From the point of view of the spoken language, its closest relatives are Ukrainian and Belarusian, the other two national languages in the East Slavic group. In many places in Ukraine and Belarus, these languages are spoken interchangeably, and in certain areas traditional bilinguism resulted in language mixture, e.g. Surzhik in central Ukraine.
Russian is primarily spoken in Russia and, to a lesser extent, the other countries that were once constituent republics of the USSR. Until 1917, it was the sole official language of the Russian Empire. During the Soviet period, the policy toward the languages of the various other ethnic groups fluctuated in practice. Though each of the constituent republics had its own official language, the unifying role and superior status was reserved for Russian. Following the break-up of 1991, several of the newly independent states have encouraged their native languages, which has partly reversed the privileged status of Russian, though its role as the language of post-Soviet national intercourse throughout the region has continued.
Russian is the official language of Russia, and an official language of Belarus, Kazakhstan, Kyrgyzstan, the Autonomous Republic of Crimea and the unrecognized Transnistria, South Ossetia and Abkhazia. It is one of the six official languages of the United Nations. Education in Russian is still a popular choice for many of the both native and RSL (Russian as a second language) speakers in Russia and many of the former Soviet republics.
97% of the public school students of Russia, 75% in Belarus, 41% in Kazakhstan, 25% in Ukraine, 23% in Kyrgyzstan, 21% in Moldova, 7% in Azerbaijan, 5% in Georgia and 2% in Armenia and Tajikistan receive their education only or mostly in Russian, although the corresponding percentage of ethnic Russians was 78% in Russia, 10% in Belarus, 26% in Kazakhstan, 17% in Ukraine, 9% in Kyrgyzstan, 6% in Moldova, 2% in Azerbaijan, 1.5% in Georgia and less than 1% in both Armenia and Tajikistan.