Russian is the most geographically widespread language of Eurasia and the most widely spoken of the Slavic languages. Russian belongs to the family of Indo-European languages and is one of three (or, according to some authorities, four) living members of the East Slavic languages; the others being Belarusian and Ukrainian (and possibly Rusyn, often considered a dialect of Ukrainian).
Written examples of Old East Slavonic are attested from the 10th century onwards. Today Russian is widely used outside Russia. Over a quarter of the world's scientific literature is published in Russian. It is also applied as a means of coding and storage of universal knowledge — 60–70% of all world information is published in English and Russian languages. Russian also is a necessary accessory of world communications systems (broadcasts, air- and space communication, etc). Due to the status of the Soviet Union as a superpower, Russian had great political importance in the 20th century. Hence, the language is still one of the official languages of the United Nations.
Russian distinguishes between consonant phonemes with palatal secondary articulation and those without, the so-called soft and hard sounds. This distinction is found between pairs of almost all consonants and is one of the most distinguishing features of the language. Another important aspect is the reduction of unstressed vowels, which is not entirely unlike that of English. Stress in Russian is neither indicated orthographically, nor governed by phonological rules.