Что это за язык? is a Russian sentence, which is detected as Bulgarian (bul 1, rus 0.938953488372093, mkd 0.9353197674418605). However, neither Bulgarian nor Macedonian have the letters э and ы in their alphabets.

Same with Чекаю цієї хвилини., which is Ukrainian, but is detected as Northern Uzbek with probability 1 whereas Ukrainian gets only 0.33999999999999997. However, the letters є and ї are used only in Ukrainian whereas the Uzbek Cyrillic alphabet doesn't include as many as five letters from this sentence, namely: ю, ц, і, є and ї.

I know that Franc is supposed to be not good with short input strings, but taking alphabets into account seems to be a promising way to improve the accuracy.