Ukrainian belongs to the Indo-European language family. It is an East Slavic language. Ukrainian evolved from Old East Slavic through the raising of mid vowels. Коть became кiть and печь became пiч. Moreover, the consonant г [g] became the voiced glottal fricative [ɦ] in Ukrainian. This shift can be explained by contact with Scythian populations in the early Middle Ages.
In the 13th century, the Eastern region which is now Ukraine came under Tatar rule and then under the Tsardom of Muscovy. The South and West of the region came under the Grand Duchy of Lithuania. While Lithuanian rule allowed for local autonomy of languages, Polish rule under the Polish-Lithuanian Commonwealth sought to establish a hegemony over spoken language. This resulted in a large influence of Polish on the development of the Ukrainian language like in the word завжди from the zawżdy (always).
In 1654, the territory of modern Ukraine was divided between the Polish-Lithuanian Commonwealth and the Tsardom of Russia in the Pereiaslav Agreement. This resulted in a Polonization and Russification of the languages spoken in their respective regions.
Moreover, during the Soviet Period, while there was no official language policy, the de facto enforcement of the Russian Language and its status as the lingua franca of the whole USSR saw a loss of the use of Ukrainian language. This history informs my perception of Ukrainian as a language of resistance and national pride.
Languages change over time through contact with different cultures around the world. Linguists track these changes through the creation of trees which show genealogical relationships between languages.