誰(だれ)か

Forms

誰(だれ) (who) + か (question particle) = someone

COMMON PATTERNS (indefinite words):
Question word + か = indefinite:

• 誰(だれ)か: someone
• 何(なに)か: something
• どこか: somewhere
• いつか: sometime
• 何(なん)とか: somehow

COMMON PATTERNS (negative words):

• 誰(だれ)も〜ない: no one
• 何(なに)も〜ない: nothing
• どこも〜ない: nowhere

か VS も: か makes the question word indefinite and positive (someone, something); も with a negative verb makes it universally negative (no one, nothing). The pair is the standard way Japanese expresses English 'some-' and 'no-' words.

Common patterns

• 誰(だれ)かいますか: Is anyone there?
• 誰(だれ)かに聞(き)く: to ask someone
• 誰(だれ)か来(き)た: Someone came

In questions, 誰(だれ)か is often best translated 'anyone' rather than 'someone': 誰(だれ)かいませんか is 'Is anyone there?'