疑問・語気 · Questions & tone
か
Question marker
Placed at the end of a sentence (or after a question word) to mark a question. Can also mean "or" between nouns.
When to use
- 行きますか = Will you go?
- 何か食べる？ = Eat something?
- コーヒーか紅茶 = coffee or tea
How to use
- 1Add か at the end of a plain or polite clause for questions.
- 2Do not use か with ですか double-marking in beginner patterns — ですか is one unit.
- 3のか adds explanatory or surprised questioning tone.
Nuance & non-standard uses
Patterns that go beyond the textbook default — contrast, omission, register shifts, and mixed particles.
のか — probing "why / how come"
のか (and casual んか) asks for an explanation, sometimes with surprise or challenge: どうしたのか, 本当に行くのか. The の nominalizes; か questions the whole situation.
まだ食べるの？
You're still eating? — surprised check.
何を言っているのか分からない。
I don't understand what (they) are saying — embedded question.
か as doubt inside embedded clauses
か after a plain clause inside a larger sentence marks indirect question or uncertainty: 行くかどうか, 来るか分からない. Not sentence-final intonation — grammatical subordination.
彼が来るかどうかは不明だ。
Whether he will come is unclear.
これでいいか確認して。
Check if this is okay.
かもしれない / かも — epistemic maybe
か in かもしれない is not a yes/no question marker — it is part of a modal meaning "might." Treat かも as a chunk when teaching; splitting it confuses learners.
雨かもしれない。
It might rain — epistemic, not a question.
Rising か on statements (masculine / rough register)
Some speakers end statements with か for blunt or rough tone (本当にそうか). This is not a question — register marker. Avoid in polite です/ます unless mimicking that voice.
そうか。
I see / oh — acknowledgement, not always a question.
Examples
これは本ですか。
Is this a book?
土曜日か日曜日に行く。
Go on Saturday or Sunday.