If an interrogative sentence does not contain an interrogative pronoun
or adverb, its character is marked by adding the particle =ko= or =kö=
to some word in the sentence. Thus one says =menettekö kotiin?= _are you
going home?_ But in such sentences as =mihin menette?= or =kuka menee?=
it is unnecessary to use =ko=, as the sentence already contains a word
which makes its interrogative character clear. It will be noticed that
this use of =ko= is exactly similar to that of =ли= in Russian.
The termination =ko=, =kö= is added to the word on which the chief
interrogative stress is laid.
=Tiedättekö mihin hän on lähtenyt?= _do you know where he is gone?_
=Isäkö sen sanoi?= _was it the father who said so?_ =Meritsekö aiotte
matkustaa?= _are you thinking of going by sea?_
In a negative question the termination =kö= is always attached to the
negative verb. =Ettekö ole nähneet häntä?= _have you not seen him?_ =Eikö
jo lakkaa satamasta?= _hasn’t it stopped raining yet?_
In a disjunctive question the particle =ko=, =kö= is attached to the
first alternative which is connected with the second by the word =vai=.
=Poikako se on vai tyttö?= _is that a boy or a girl?_
But if there are two verbs in the sentence =ko= or =kö= is added to each.
=Onko hän vielä kotona vai läksikö?= _is he still at home or has he
started?_
In such a sentence as, _Are you coming or not?_ one can say either
=Tuletteko vai ette?= or, =tuletteko vai ettekö tule?=
The manner of giving a negative reply has been described above. Though
there are two words, =ja= and =niin= (instr. plural of =se=), which can
be used for ‘yes,’ the usual way of giving an affirmative reply is, to
repeat the word which in the question has =ko= attached to it. =Tuliko
pappi?= _has the priest come?_ =Tuli=, _yes_.