In the 12th century, a specific sound shift began to reshape the speech of Kievan Rus. Old East Slavic words like kotъ /kote/ for cat evolved into kit /kit/ in modern Ukrainian. This change involved raising and lengthening mid vowels when followed by a consonant and a weak yer vowel that eventually disappeared completely. The same process turned pech /petsh/ into pich /pich/ for oven. These phonological developments did not happen in Russian, which retained the original vowel sounds. Only Belarusian shared one feature with Ukrainian: the fricativisation of the Old East Slavic consonant g /g/. That sound likely first became /gh/ in the 13th century before evolving into /h/ as it exists today.
Linguists have debated whether a common Old East Slavic language ever existed at all. Some scholars argue that diversification took place in the 8th or early 9th century during prehistoric times. Others claim that dialects of East Slavic tribes evolved gradually from Proto-Slavic without any intermediate stages between the 6th and 9th centuries. Stepan Smal-Stotsky denied the existence of a common Old East Slavic language at any time in the past. He believed that Ukrainian formed through the convergence of tribal dialects due to intensive migration within what is now Ukraine. George Shevelov supported this view with phonological studies showing specific features recognizable in southern dialects as far back as they can be documented.
Imperial Suppression Policies
The tsarist interior minister Pyotr Valuyev issued a decree in 1863 stating there never has been, is not, and never can be a separate Little Russian language. This proclamation banned the use of Ukrainian as a subject and language of instruction in schools across the empire. The same year, Taras Shevchenko was arrested and exiled for ten years on political grounds. He received a ban preventing him from writing or painting again. Pavlo Chubynsky faced seven years of exile to Arkhangelsk in 1862 after his arrest.
A secret Ems Ukaz followed the Valuyev circular to prohibit publication and importation of most Ukrainian-language books. Public performances and lectures were also banned under these restrictions. Even printing Ukrainian texts accompanying musical scores became illegal. A period of leniency appeared after 1905 before another strict ban took effect in 1914 affecting Russian-occupied Galicia. Despite these measures, many writers moved to Austrian Galicia where rules remained more liberal. They published works that were then smuggled eastward into Russian-controlled territories. By the time of the Russian Revolution of 1917, Ukrainians had developed enough national literature to form an independent state.