Learn Hardcore Russian: Суффикс «-то» показывает, что мы говорим о чём‑то неопределённом, но существующем. - The suffix “-то” shows that we are talking about something indefinite but real.

Yes, суффикс is the Russian word for suffix – a meaningful element that is attached to the end of a word (or word stem) and changes its meaning or function.

In Russian school grammar, -то in кто-то, что-то is sometimes called a постфикс (postfix) rather than a classic derivational suffix, because it’s stuck on after the whole word (not just the stem). But for a learner, you can safely think of суффикс -то as “the suffix -то added to pronouns/adverbs to give them an indefinite meaning.”

Why is -то written with a hyphen and not as a separate word?

-то is a bound morpheme: it can’t stand alone, it only attaches to certain pronouns and adverbs. In Russian orthography, such elements are typically written with a hyphen:

кто-то – someone
что-то – something
где-то – somewhere
когда-то – sometime
какой-то – some (kind of)

Writing it as two words (кто то) would be wrong and would look like кто (who) + то (the particle/word “that”), which changes the structure and is ungrammatical in this meaning.

What does -то actually add to the meaning? How is it “indefinite but existing”?

-то marks something as:

indefinite / not specified: the speaker doesn’t say exactly which person/thing/place,
but real / existing in the speaker’s mind: the speaker assumes that this person/thing/place actually exists.

Compare:

Кто-то звонил. – Someone called.
→ I don’t say who, but I believe a real person called.

This is different from English anyone/anything, which can sometimes be used in contexts where it might not exist. With -то, the default idea is: there really is such a person/thing, I just don’t know or won’t specify which one.

How is -то different from -нибудь, as in кто-нибудь, что-нибудь?

Both -то and -нибудь create indefinite pronouns, but their nuance is different:

-то = indefinite, but definitely existing / specific in the speaker’s mind
- Кто-то стучит в дверь. – Someone is knocking at the door.
  (There really is some person; I hear the knocking.)
-нибудь = indefinite, often hypothetical / “any”
- Если кто-нибудь придёт, открой дверь. – If anyone comes, open the door.
  (Maybe someone will, maybe no one; it’s hypothetical.)

So суффикс -то in the sentence is specifically talking about that “indefinite but existing” type of reference, as opposed to the more open, “anyone at all, maybe no one” sense of -нибудь.

In о чём‑то, what form is чём‑то and why does it look like that?

Чём‑то is:

from the pronoun что – what / something
in the prepositional case (after о) → чём
with the suffix -то attached → чём‑то

So:

что (nominative) – what
о чём – about what
о чём‑то – about something (indefinite but existing)

The ё and the ending correspond to the normal prepositional case of что; -то just gets added after the full case form.

Why are неопределённом and существующем in that exact form?

They both agree with the implied neuter noun что‑то (something) in:

case: prepositional (after о → “about”)
gender: neuter
number: singular

So:

неопределённый (indefinite) → неопределённом (prep., masc./neut. sg.)
существующий (existing) → существующем (prep., masc./neut. sg.)

Full structure:

о чём‑то неопределённом, но существующем
→ about something (that is) indefinite, but existing.

Grammatically, неопределённом and существующем are shortened forms of full adjectives / participles used as attributes and must match the noun they describe.

What is the nuance of “неопределённом, но существующем”? Why both adjectives?

Together they specify two separate ideas:

неопределённом – indefinite, not clearly defined or specified.
существующем – actually existing (real), not imaginary or nonexistent.

So the phrase says: when we use -то, we’re talking about something that:

we don’t identify precisely (indefinite),
but we still treat as real, as actually there.

This contrasts with things like pure hypotheticals, where the thing may or may not exist in reality (more like what -нибудь often suggests).

Why is there a comma before что in показывает, что мы говорим?

In Russian, a comma is placed before что when it introduces a subordinate clause (a dependent clause) that explains or completes the meaning of the main clause.

Main clause: Суффикс -то показывает – The suffix -то shows
Subordinate clause: что мы говорим о чём‑то неопределённом, но существующем – that we are speaking about something indefinite but existing.

So что here is a subordinating conjunction, and Russian punctuation rules require a comma before it in this function.

Why is it мы говорим (“we speak”) and not something more impersonal, like “one speaks”?

Russian often uses мы (“we”) in explanations or general statements to mean “we (people in general / speakers of the language)”, not a specific group.

So:

…показывает, что мы говорим о чём‑то…
→ “…shows that we are talking about something…”

You could paraphrase it in English as:

“shows that you / one / people are talking about something indefinite but existing.”

Using мы is a common way in Russian pedagogical or explanatory style to make the rule feel inclusive and general, not tied to a specific person.

Is существующем just an adjective, or is it something like a participle?

Существующем comes from the verb существовать (to exist) and is:

a present active participle: существующий – “existing”
used here adjectivally, agreeing with the (implied) neuter noun что‑то in the prepositional case: существующем.

So grammatically it’s a participle form, but in this sentence it functions like an adjective: it simply describes the noun (“something existing”).

What kinds of words can take the suffix -то? Is it only pronouns like что and кто?

It’s most common with interrogative pronouns and adverbs, where it turns them into indefinite words:

Pronouns:
- кто-то – someone
- что-то – something
- какой-то – some kind of
- чей-то – someone’s
Adverbs:
- где-то – somewhere
- когда-то – sometime (once / at some time)
- как-то – somehow
- почему-то – for some reason
- зачем-то – for some (unspecified) purpose

All of these share the core idea from the sentence: indefinite, but treated as real / existing.