Serbocroatin (latin) works for Serbian-Latin and English. On pages on Russian language it works for latin words only.
Russian website is on same domain as Serbian and English and there is no any additional settings.
GELERAL SCOPE TAB
Everything is checked.
HYPHENATION TAB
Checked:
Enable hyphenation. (language is Sebocroatian (latin))
Allow hyphenation of words that begin with a capital letter.
Allow hyphenation of the components of hyphenated compound words.
Remove hyphenation when copying to clipboard
Add workaround for Safari hyphenation bug
OTHER
Do not hyphenate words with less than 4 letters.
Keep at least 2 letters before hyphenation.
Keep at least 2 letters after hyphenation.
SPACE CONTROLS TAB
Prevent widow is not checked.