Ukrainian and Russian are very closely related languages, but are not as similar as many might think.
Despite sharing the Cyrillic script and a similar grammar structure, the two languages have many major and minor differences that set them apart from one another.
Most Ukrainians also speak Russian or at least have a large amount of exposure to it, while only a very small number of Russians speak Ukrainian.
This means that there is asymmetrical mutual intelligibility, which is to say that Ukrainians who don’t speak Russian fluently can understand Russian much better than Russians who don’t speak Ukrainian fluently can understand Ukrainian.
Most Ukrainians can speak Russian, but very few Russians can speak Ukrainian
In most of Ukraine, Ukrainian is the dominant language. However, in eastern parts of the country, Russian is spoken quite frequently.
A number of Ukrainians also speak Surzhyk in their daily lives, which is a mixture of both Russian and Ukrainian.
According to a survey from the Razumkov Centre in 2015, 60% of Ukrainians consider Ukrainian to be their native language, 15% consider it to be Russian, and 22% believe both are their mother tongues.
This doesn’t include Crimea, which was annexed in 2014, or Luhansk and Donetsk, which have Russian-speaking majorities.
Russian and Ukrainian are both considered Slavic languages, which means they developed from Old East Slavic, the language used in Kievan Rus’, a federation of states in Eastern Europe which was formed in the 9th century.
There are three subgroups of Slavic languages: East Slavic, which includes Russian, Belarusian, and Ukrainian; West Slavic, of which Polish, Czech, and Slovak are a part; and South Slavic, which includes Slovene, Croatian, Northern Macedonian, and Bulgarian.
All of these languages share a common linguistic ancestor in Proto-Slavic, an ancient proto-language used from the second millennium BC up until the 6th century AD.
Proto-Slavic is a branch of Proto-Indo-European (PIE), an ancient proto-language which is considered the mother language of tongues spoken across Europe, parts of West Asia, and the Indian subcontinent. Languages that come from PIE include Greek, Hindi, Italian, Persian, and many others.
In the Kievan Rus’, Russian and Ukrainian were dialects of the same language, meaning that they were largely mutually intelligible with only minor vocabulary or grammatical differences.
When Kievan Rus’ fell to the Mongols in the 13th century, the formerly united states became split, and what were once very closely-related dialects began to grow and become more and more distinct.
During this period, the Russian language was shaped and influenced by Old Church Slavonic, a formal language mainly used in literary texts. Meanwhile, Ukrainian did not take much influence from Old Church Slavonic — instead, it developed from a spoken vernacular.
Additionally, Ukraine went under the control of the Grand Duchy of Lithuania, a Polish and Lithuanian commonwealth, after the fall of Kievan Rus’, much like other western states which were once part of the federation.
Due to this political influence, as well as geographical proximity, the Ukrainian language became heavily influenced by Polish, and adopted many words from the language into its vernacular. Notably, Polish was the lingua franca, or common tongue, in many of the western states once included in Kievan Rus’.
For its part, Russian began to adopt many French and other European words under the rule of Peter the Great in the seventeenth century, as he campaigned to make Russia into a more European country.
The two languages do not share as much vocabulary as one may think
So, while they share common roots, the Ukrainian and Russian tongues have developed distinctly over centuries, which has produced many differences between the two.
In terms of vocabulary, Russian and Ukrainian share about 62% lexical similarity, which doesn’t necessarily mean that they have 62% of their vocabulary in common; rather, that 62% of their vocabulary are words with similar meaning and form and are from the same origin. For example, English and German share 60% lexical similarity.
This is considered a low percentage of lexical similarity for closely related languages. Ukrainian actually has a higher lexical similarity with other Slavic languages — it has 84% similarity with Belarusian, 70% with Polish, and 66% with Slovak.
This lexical dissimilarity between Russian and Ukrainian can be explained both by different influences from other languages as well Russian’s connection to Old Church Slavonic and Ukrainian’s links to local vernacular after the fall of Kievan Rus’.
The most stark example of this difference can be shown through the different names for the months in Russian and Ukrainian.
In Russian, the names of the months come directly from Old Church Slavonic, which took them from Latin, while in Ukrainian they come from local vernacular.
January in Russian is январь, or yanvar, while in Ukrainian it is січень, or sichyen. In Russian, February is февраль or fevral, and in Ukrainian it is лютий, or lyotiy.
The Russian names may seem very familiar to English speakers, since our names for the months of the year also come from Latin through French.
The most obvious similarity between the two languages is, of course, their shared use of the Cyrillic script. Cyrillic, which was formulated in the ninth century, is largely based on the Greek alphabet.
It is named after St. Cyril, who, along with his brother St. Methodius, developed the first Slavic script, called the Glagolitic script, which was used to transcribe Old Church Slavonic.
While they share the same script, the languages have a slightly different alphabet, as some of the same sounds are expressed using different letters in both languages, and some letters that are found in Ukrainian are not found in Russian, and vice versa.
Additionally, some of the same letters are pronounced slightly — or very — differently in the two languages.
Ukrainian and Russian grammar is quite similar
In terms of grammar, Ukrainian and Russian are very similar, however. They are both heavily inflected languages, as is Greek, which means that words are changed depending on their use in a sentence.
Nouns, pronouns, adjectives are inflected depending on their gender, number, and case.
This means that words will likely change if they are the subject, verb, object, or indirect object in the sentence, and may look different when they are masculine, feminine, or neuter, or singular or plural.
These differences are usually shown in the ending of the noun, pronoun, or adjective.
In terms of verbs, they can change depending on their tense, number, voice, or mood, depending on the language.
Ukrainian and Russian both have three noun genders — feminine, masculine, and neuter, much like Greek.
Russian has six noun cases — nominative (for subjects), genitive (for possession), dative (for indirect objects), accusative (for direct objects), instrumental (indicates means), and prepositional (used only with prepositions).
Ukrainian has all of these noun cases, plus one more — vocative. Vocative is used in direct address, most commonly with someone’s name.
Russian used to have a vocative case, but it largely fell out of use except for in very few instances, such as when a person addresses God.
Noun endings are very similar in Ukrainian and Russian, and often only differ only by a few letters because different sounds are expressed with different letters in the two languages.