Russian is an East Slavic language and an official language in Russia, Belarus, Kazakhstan, Kyrgyzstan and many minor or unrecognised territories. It is an unofficial but widely spoken language in Ukraine, and to a lesser extent, the other countries that were once constituent republics of the Soviet Union and former participants of the Eastern Bloc.

Russian belongs to the family of Indo-European languages and is one of the four living members of the East Slavic languages. Written examples of Old East Slavonic are attested from the 10th century and beyond.

　　It is the most geographically widespread language of Eurasia and the most widely spoken of the Slavic languages. It is also the largest native language in Europe, with 144 million native speakers inRussia, Ukraine and Belarus. Russian is the eighth most spoken language in the world by number of native speakers and the seventh by total number of speakers. The language is one of the six official languages of the United Nations. Russian is also the second most widespread language on the Internet after English.

　　Russian distinguishes between consonant phonemes with palatal secondary articulation and those without, the so-called soft and hard sounds. Almost every consonant has a hard or a soft counterpart, and the distinction is a prominent feature of the language. Another important aspect is the reduction of unstressed vowels. Stress, which is unpredictable, is not normally indicatedorthographically though an optional acute accent (знак ударения, znak udareniya) may be used to mark stress, such as to distinguish between homographic words, for example замо́к (zamók, meaning a lock) and за́мок (zámok, meaning a castle), or to indicate the proper pronunciation of uncommon words or names.