Yes/No Questions by Type: Tuletko? Onko sinulla?

Every Finnish yes/no question is built the same mechanical way: you take the finite verb, glue the clitic -ko/-kö onto it, and move it to the front — Tuletko? ("Are you coming?"). That single mechanism is covered in full on the question clitic -ko/-kö page (harmony, placement, the fact that it is one word — never tulet ko). What that page does not tell you is that the rest of the sentence changes shape depending on what kind of thing you are asking about. This page sorts yes/no questions into their four everyday types, because each type puts a different case on its noun — and getting that case wrong is what actually marks an English speaker as a beginner.

Type 1 — Verb questions: is the action happening?

The plain case: you want to know whether someone does, is doing, or will do something. The clitic sits on the ordinary personal verb form, and the subject pronoun is usually dropped because the ending already carries the person.

Note there is no word for "do". English props questions up with do / does / did; Finnish has no such auxiliary and needs none — Puhutko? is a whole question by itself.

Type 2 — Existential questions: does it exist / is there any?

To ask whether something exists or is available somewhere, you front the verb olla as Onko and — crucially — put the thing itself in the partitive. This is the question form of the existential sentence: a location or nothing at all, then onko, then a partitive noun.

The partitive (kahvilaa, maitoa, tilaa) is doing real work here: it frames the noun as an indefinite, unbounded "any" — exactly the "is there any…?" of English. A nominative there would sound like you are pointing at one specific, already-known café.

Type 3 — Possessive questions: do you have…?

Finnish has no verb "to have". "Do you have X?" is literally "Is there X at you?" — the possessor goes in the adessive -lla/-llä, olla fronts as Onko, and the possessed thing again typically takes the partitive. This is the question form of the possessive sentence.

The whole burden of "you have" is carried by sinulla / teillä — the person in the adessive. There is no separate word for "have" to reach for, and reaching for one (or leaving the person in the nominative sinä) is the number-one beginner error in this type.

Type 4 — Identity and predicate questions: is X a Y?

To ask whether something is something — a teacher, yours, new, here — you again front olla, but now the complement is a plain nominative predicate, not a partitive. This is the question form of the predicate nominal.

Watch olla agree with its subject just as in a statement: onko for a singular subject, ovatko for a plural one (he). And note the contrast with Type 2: an existential Onko täällä opettajaa? ("Is there a teacher here?", partitive) asks whether one exists, while an identity Onko hän opettaja? ("Is he a teacher?", nominative) asks what a known person is.

A quick note on the reply: Finnish does not answer these with a bare "yes/no" but by echoing the fronted verb — Tuletko? — Tulen. / Onko sinulla aikaa? — On. / Ei ole. That system has its own page; see answering yes/no questions.

Common Mistakes

Key Takeaways

• The mechanism is always the same clitic -ko/-kö on a fronted verb — the -ko page has the details. What changes is the sentence frame.
• Verb questions: clitic on the ordinary verb, no "do" — Puhutko suomea?
• Existential questions: Onko
  • location + partitive — Onko maitoa?
• Possessive questions: Onko
  • person in the adessive
    • partitive — Onko sinulla aikaa?
• Identity/predicate questions: Onko / Oletko
  • nominative predicate — Oletko opettaja?
• Getting the case right (partitive vs nominative; adessive on the possessor) matters more than anything else once the clitic is in place.