East Slavic languages

The East Slavic languages constitute one of three regional subgroups of the Slavic languages, distinct from the West and South Slavic languages. East Slavic languages are currently spoken natively throughout Eastern Europe, and eastwards to Siberia and the Russian Far East. In part due to the large historical influence of the Russian Empire and the Soviet Union, the Russian language is also spoken as a lingua franca in many regions of Caucasus and Central Asia. Of the three Slavic branches, East Slavic is the most spoken, with the number of native speakers larger than the Western and Southern branches combined.

The common consensus is that Belarusian, Russian and Ukrainian are the extant East Slavic languages. Some linguists also consider Rusyn a separate language, although it is sometimes considered a dialect of Ukrainian.

The modern East Slavic languages descend from a common predecessor spoken in Kievan Rus' from the 9th to 13th centuries, which later evolved into Ruthenian, the chancery language of the Grand Duchy of Lithuania in the Dnieper river valley, and into medieval Russian in the Volga river valley, the language of the Russian principalities including the Grand Duchy of Moscow.

All these languages use the Cyrillic script, but with particular modifications. Belarusian and Ukrainian, which are descendants of Ruthenian, have a tradition of using Latin-based alphabets—the Belarusian Łacinka and the Ukrainian Latynka alphabets, respectively (also Rusyn uses Latin in some regions, e.g. in Slovakia). The Latin alphabet is traditionally more common in Belarus, while the usage of the Cyrillic script in Russia and Ukraine could never be compared to any other alphabet.

Classification
Modern East Slavic languages include Belarusian, Russian and Ukrainian. The Rusyn language is sometimes considered the fourth living language of the group, its status as an independent language being the subject of scientific debate.

Vocabulary
The East Slavic territory exhibits a linguistic continuum with many transitional dialects. Between Belarusian and Ukrainian there is the Polesian dialect, which shares features from both languages. East Polesian is a transitional variety between Belarusian and Ukrainian on one hand, and between South Russian and Ukrainian on the other hand. At the same time, Belarusian and Southern Russian form a continuous area, making it virtually impossible to draw a line between the two languages. Central or Middle Russian (with its Moscow sub-dialect), the transitional step between the North and the South, became a base for the Russian literary standard. Northern Russian with its predecessor, the Old Novgorod dialect, has many original and archaic features.

Ruthenian, the ancestor of modern Belarusian and Ukrainian, was the official language of the Grand Duchy of Lithuania as "Chancery Slavonic" until the end of the 17th century when it was gradually replaced by the Polish language. It was also the native language of the Cossack Hetmanate until the end of the 18th century, when the Ukrainian state completely became part of the Russian Empire in 1764. The Constitution of Pylyp Orlyk from 1710 is one of the most important written sources of the Ruthenian language. Due to the influence of the Polish–Lithuanian Commonwealth over many centuries, Belarusian and Ukrainian have been influenced in several respects by Polish, a Lechitic West Slavic language. As a result of the long Polish-Lithuanian rule, these languages had been less exposed to Church Slavonic, featuring therefore less Church Slavonicisms than the modern Russian language, for example: Additionally, the original East Slavic phonetic form was kept in many words in Ukrainian and Belarusian, for example: In general, Ukrainian and Belarusian are also closer to other Western European languages, especially to German (via Polish). At the same time Russian was being heavily influenced by Church Slavonic (South Slavic language), but also by the Turkic and Uralic languages. For example: What's more, all three languages do also have false friends, that sometimes can lead to (big) misunderstandings. For example, Ukrainian орати (oraty) — "to plow" and Russian орать (orat́) — "to scream", or Ukrainian помітити (pomityty) — "to notice" and Russian пометить (pometit́) — "to mark".

Alphabet
The alphabets of the East Slavic languages are all written in the Cyrillic script, however each of them has their own letters and pronunciations. Russian and Ukrainian have 33 letters, while Belarusian has 32. Additionally, Belarusian and Ukrainian use the apostrophe (') for the hard sign, which has the same function as the letter Ъ in Russian. Some letters, that are not included in the alphabet of a language, can be written as diagraphs. For example, the letter Ё, which doesn't exist in the Ukrainian alphabet, can be written as ЙО (ЬО before and after consonants), while the letter Щ is written as ШЧ in Belarusian (compare Belarusian плошча and Ukrainian площа ("area")).

There are also different rules of usage for certain letters, e.g. the soft sign (Ь) cannot be written before and after the letter Ц in Russian, because such combination straightforwardly doesn't exist in the Russian language, while in Ukrainian and especially Belarusian, on the contrary, it's a relatively common maneuver. Moreover, the Russian Щ is always pronounced softly (palatalization).

Standard Ukrainian, unlike all the other Slavic languages (excl. Serbo-Croatian), does not exhibit final devoicing. Nevertheless, this rule is not that clear when listening to colloquial Ukrainian. It's one of the typical deviations that occur in the Ukrainian spoken language.

Other orthographic differentiations (false friends)
Besides the differences of the alphabets, there are also quite many false friends. For example, one of the common false friends, the letter И (romanized as I for Russian and Y for Ukrainian), which in Russian is mostly pronounced as (identical with the Ukrainian І), while in Ukrainian it's mostly pronounced as  (very similar to the Russian Ы). Other examples:

Influence of Church Slavonic
After the conversion of the East Slavic region to Christianity the people used service books borrowed from Bulgaria, which were written in Old Church Slavonic (a South Slavic language). The Church Slavonic language was strictly used only in text, while the colloquial language of the Bulgarians was communicated in its spoken form.

Throughout the Middle Ages (and in some way up to the present day) there existed a duality between the Church Slavonic language used as some kind of 'higher' register (not only) in religious texts and the popular tongue used as a 'lower' register for secular texts. It has been suggested to describe this situation as diglossia, although there do exist mixed texts where it is sometimes very hard to determine why a given author used a popular or a Church Slavonic form in a given context. Church Slavonic was a major factor in the evolution of modern Russian, where there still exists a "high stratum" of words that were imported from this language.