Belarus–Ukraine relations
Belarus–Ukraine relations (, "Byelaruska-ŭkrainskiya adnosiny", , "Ukrains'ko-Bilorus'ki vidnosyny", , "Belorussko-ukrainskiye otnosheniya") are foreign relations between Belarus and Ukraine. Both countries were successively ruled by the Polish-Lithuanian Commonwealth, the Second Polish Republic, and ultimately, the Russian Empire. Prior to the 1991 breakup, both countries were part of the Soviet Union as the Belarusian SSR and Ukrainian SSR when they were the founding members of the United Nations in 1945. Being Slavic nations, both Belarus and Ukraine share closely related cultures and are predominantly inhabited by the East Slavic ethnic groups of Belarusians and Ukrainians respectively, along with a few Russians. Today, the two countries share an 891–km border.
East Slavic languages
The East Slavic languages constitute one of three regional subgroups of Slavic languages, currently spoken throughout Eastern Europe, Northern Asia, and the Caucasus. It is the group with the largest numbers of speakers, far out-numbering the Western and Southern Slavic groups. The existing East Slavic languages are Belarusian, Russian and Ukrainian; Rusyn is considered to be either a separate language or a dialect of Ukrainian.