Russian (ру́сский язы́к, russky yazyk, pronounced [ˈruskʲɪj jɪˈzɨk]) is an East Slavic language and an official language in Russia, Belarus,Kazakhstan, and Kyrgyzstan. It is an unofficial but widely spoken language in Ukraine, Moldova, Latvia, Lithuania, Estonia, and to a lesser extent, the other countries that were once constituent republicsof the Soviet Union and former participants of the Eastern Bloc. Russian belongs to the family of Indo-European languages and is one of the three living members of the East Slavic languages. Written examples of Old East Slavonic are attested from the 10th century onwards. Classification Russian is a Slavic language of the Indo-European family. It is a lineal descendant of the language used in Kievan Rus'. From the point of view of the spoken language, its closest relatives are Ukrainian, Belarusian, and Rusyn, the other three languages in the East Slavic group. In many places in eastern and southern Ukraine and throughout Belarus, these languages are spoken interchangeably, and in certain areas traditional bilingualism resulted in language mixtures, e.g. Surzhyk in eastern Ukraine and Trasianka in Belarus. Geographical distribution 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, although it was declared the official language only in 1990. Dialects Russian is a rather homogeneous language, in terms of dialectal variation, due to the early political centralization under the Moscow rule, compulsory education, mass migration from rural to urban areas in the 20th century, as well as other factors. The standard language is used in written and spoken form almost everywhere in the country, from Kaliningrad and Saint Petersburg in the West to Vladivostok and Petropavlovsk-Kamchatsky in the East, notwithstanding the enormous distance in between.