Russian language
Despite leveling after 1900, especially in matters of vocabulary and phonetics, a number of dialects still exist in Russia. Some linguists divide the dialects of Russian into two primary regional groupings, "Northern" and "Southern", with Moscow lying on the zone of transition between the two. Others divide the language into three groupings, Northern, Central (or Middle) and Southern, with Moscow lying in the Central region. All dialects also divided in two main chronological categories: the dialects of primary formation (the territory of the Eastern Rus' or Muscovy, roughly consists of the modern Central and Northwestern Federal districts); and secondary formation (other territory). Dialectology within Russia recognizes dozens of smaller-scale variants. The dialects often show distinct and non-standard features of pronunciation and intonation, vocabulary and grammar. Some of these are relics of ancient usage now completely discarded by the standard language.

Q: What distinguishes Russian dialects?
non-standard features of pronunciation and intonation, vocabulary and grammar