"A sister is eating with a brother."
Translation:Сестра їсть з братом.
Don't transliterate it. If "yist'" doesn't work, then it's a broken system. You really have to know a language's alphabet in order to properly read and write it. And it's not just because of the Cyrillic alphabet. Same goes with any alphabet. In Polish "Warszawa," the capital, is pronounced "Varshava." Does that mean you should transliterate? Or learn the Polish alphabet?