English has one word, “someone”. Russian has three, and they say different things: whether you know who it is, whether it matters, and whether you’re keeping it to yourself. All of them are built from question words you already know.
A2–B111 min read-то · -нибудь · ко́е-3 particles
Three particles on the same question word кто (who). Each tells the listener how much the speaker knows.
The short answer
Take a question word (кто who, что what, где where) and add a particle. -то means a real, particular thing whose identity you don’t know. -нибудь means any one at all, and appears in questions, requests and the future. ко́е- means one you know but aren’t naming. The question-word part changes for case; the particle never does.
A pronoun is a word that stands in for a noun (“he”, “it”, “someone”). A particle is a small add-on that changes a word’s meaning without being a word on its own. Russian makes all its “some-” and “any-” words by joining a particle to a question word with a hyphen. Learn the eight question words and you get twenty-four new words for free. Tap any cell to hear it.
Question word
+ -то · some (unknown)
+ -нибудь · any
ко́е- + · a certain
ктоwho
чтоwhat
гдеwhere
куда́where to
когда́when
какhow
како́йwhich, what kind
чейwhose
The particle is never stressed: кто́-то sounds like one word, KTO-ta. In ко́е- words the stress falls on ко́е and the question word keeps a light second stress. In official and academic writing you will also see -ли́бо (кто́-ли́бо, что́-ли́бо), a formal equivalent of -нибудь.
2 · The key choice
-то or -нибудь: does it already exist?
Ask one question: is there a particular person, thing or place out there right now, even if you can’t name it? If yes, use -то. If you’re asking, asking for, or imagining one, and any one will do, use -нибудь.
A useful test: if you could add “I don’t know which” in English, it’s -то. If you could add “it doesn’t matter which”, it’s -нибудь.
-то
-нибудь
One sentence, two meanings
3 · I know, but I’m not saying
ко́е-: a certain someone, a little something
ко́е- goes at the front. The speaker knows exactly who or what, but keeps it vague, to build suspense, to be modest, or to avoid listing everything. It is often playful, and ко́е-что́ (“a little something”) is what you say when handing over a present.
4 · In every case
кого́-то, чему́-нибудь: only the first half changes
Russian nouns and pronouns change their ending to show their role in the sentence (subject, object, “with”, “about” and so on). Each form is called a case. Indefinite pronouns follow their question word exactly: if кто becomes кого́, then кто́-то becomes кого́-то. The particle stays the same in every case.
Case
кто́-то · someone
что́-то · something
како́й-то · some kind of (m.)
Nominative
Genitive
Dative
Accusative
Instrumental
Prepositional
5 · The negative side
никто́ and не́кого: nobody, and nobody to
Two more prefixes complete the family. ни- makes “no-” words (nobody, nothing, nowhere) and always comes with не before the verb: Russian says “nobody not came”. Stressed не́- makes “there is no one to…” words and is followed by a verb in the infinitive (the dictionary form, like “to call”).
ни- … неnobody, nothing, nowhere, never
не́- + infinitivethere is no one / nothing / nowhere to…
With a preposition, both prefixes split off just like ко́е-: ни с кем (with nobody), не́ с кем (there’s nobody to … with). More on doubled negatives in Negation.