section_path: Classification
section_name: Classification
paragraph_text: Classification
  
  Russian is an East Slavic language of the wider Indo-European family. It is a descendant of Old East Slavic, a language used in Kievan Rus', which was a loose conglomerate of East Slavic tribes from the late 9th to the mid-13th centuries. From the point of view of spoken language, its closest relatives are Ukrainian, Belarusian, and Rusyn, the other three languages in the East Slavic branch. 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 such as Surzhyk in eastern Ukraine and Trasianka in Belarus. An East Slavic Old Novgorod dialect, although it vanished during the 15th or 16th century, is sometimes considered to have played a significant role in the formation of modern Russian. Also, Russian has notable lexical similarities with Bulgarian due to a common Church Slavonic influence on both languages, but because of later interaction in the 19th and 20th centuries, Bulgarian grammar differs markedly from Russian.
  
  Over the course of centuries, the vocabulary and literary style of Russian have also been influenced by Western and Central European languages such as Greek, Latin, Polish, Dutch, German, French, Italian, and English, and to a lesser extent the languages to the south and the east: Uralic, Turkic, Persian, Arabic, and Hebrew.
  
  According to the Defense Language Institute in Monterey, California, Russian is classified as a level III language in terms of learning difficulty for native English speakers, requiring approximately 1,100 hours of immersion instruction to achieve intermediate fluency.