1) as an interrogative particle in beginning of a sentence (direct interrogation)
2) in meaning of 'or' in cases like questions with choice provided
3) in meaning of 'wether' or 'if' in indirect interrogations
In Ruthenian, I suggest, 'чи' plays quite the same role
In Russian, 'ли' is used
1) in some forms of direct interrogations, after predicate
2) in some cases in meaning of 'or', after the word it relates to, unlike 'или'
(when it doesn't matter what to choose, for example)
3) like 3) in Polish
Are such forms of interrogation essentially the residuals of compound sentences?
Are there any examples of such fenomena in non-slavic languages?