> The short answer is simple: Ukrainians call their capital “Kyiv” (kee-yiv), the spelling, a transliteration of the Ukrainian Київ. The Russian version is “Kiev” (kee-yev).

> Not surprisingly, the Ukrainian government mounted a campaign four years ago to secure international approval for the name of its capital city. There is even a popular Twitter hashtag, #KyivNotKiev.

https://www.theguardian.com/world/2022/feb/25/how-to-pronoun...

The Ukrainian and Russian alphabets have different glyphs and pronunciations for a few letters. In Ukrainian, it is Ки́їв, and in Russian, it is Ки́ев. They Romanize differently, and it is considered a sign of solidarity with Ukraine to use their spelling/pronunciation.

Ukraine changed the "official" way to transliterate Ukrainian words from Cyrillic to English some time ago, to closer match the way it's actually pronounced. Plus some changes from Russian to Ukrainian when the country started promoting the Ukrainian language (they're very close, but not quite the same).

Kiev -> Kyiv. Kharkov -> Kharkiv. Zelensky should be spelt Zelenskiy (as per his official social media). Vladimir -> Volodymyr, Mikhail -> Mykhailo, etc...

Similarly, as a non-European, when did the "Czech Republic" becomes "Czechia" (at least on Google Maps)?

Kiev was the Russian name: https://en.wikipedia.org/wiki/KyivNotKiev