Russian is an official language in the blue areas, spoken in the green ones

Russian ( russkiy yazyk), is the most widely spoken language of Eurasia and the most widespread of the Slavic languages. Russian belongs to the family of Indo-European languages. Within the Slavic family, Russian is one of three members of the East Slavic group, the other two being Belarusian and Ukrainian.

Written examples of East Slavonic are attested from the 10th century onwards. While Russian preserves much of East Slavonic synthetic-inflexional structure and a Common Slavonic word base, modern Russian exhibits a large stock of borrowed international vocabulary for politics, science, and technology. A language of great political importance in the 20th century, Russian is one of the official languages of the United Nations.
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 spoken in Russia, former Soviet republics, former Warsaw Pact-member states, Israel, Mongolia, and Southeast Asia, with a total of speakers whose primary language it is, of about 145 million. It is the official language of Russia, Belarus, Kazakhstan, Kyrgyzstan, United Nations, Crimea, Abkhazia, Transnistria, and is regulated by the Russian Academy of Sciences