Той, хто чує дзвінок пізно ввечері, зазвичай спочатку питає, хто там.

Той, хто... literally means the one who... or whoever... in this kind of general statement.

So:

• той = that one / the one
• хто = who

Together, they form a very common Ukrainian pattern:

• Той, хто знає... = The one who knows...
• Той, хто прийшов... = The one who came...

In your sentence, Той, хто чує дзвінок... means Whoever hears the ring/call... or The person who hears the ring/call...

They do two different jobs.

1. In Той, хто чує дзвінок..., хто means who in a relative clause:

   • the one who hears...

2. In питає, хто там, хто introduces the content of the question:

   • asks who is there

So the first хто = relative who
The second хто = interrogative who

This is completely normal in Ukrainian.

The commas mark off the clause хто чує дзвінок пізно ввечері.

Structure:

• Той, хто чує дзвінок пізно ввечері, = The one who hears a ring/call late in the evening,
• зазвичай спочатку питає, хто там. = usually first asks who is there.

In Ukrainian, relative clauses like хто чує дзвінок... are set off with commas.

There is also a comma before хто там because it introduces a subordinate clause after питає:

• asks who is there

Because Ukrainian, like English, often uses the present tense for habitual or general truths.

• чує = he/she hears
• but in context it means whoever hears / when someone hears

So this is a general statement, not one single event:

• Той, хто чує дзвінок пізно ввечері, зазвичай...
• Whoever hears a ring/call late in the evening usually...

This is sometimes called the gnomic or habitual present.

Because дзвінок is the direct object of чує (hears), so it is in the accusative case.

For an inanimate masculine noun in Ukrainian, the accusative singular is usually the same as the nominative singular.

So:

• nominative: дзвінок
• accusative: дзвінок

That is why the form does not change.

If it were an animate masculine noun, the accusative would usually match the genitive instead.

Дзвінок can mean several related things depending on context:

• a ring
• a bell signal
• a phone call
• a doorbell ring

In this sentence, because of пізно ввечері and хто там (who is there?), many learners will naturally imagine a doorbell ring or someone at the door.

But the word itself is broad enough that context determines the exact meaning.

Пізно ввечері literally means late in the evening.

Breakdown:

• пізно = late
• ввечері = in the evening

So together:

• пізно ввечері = late in the evening / late at night (depending on context)

A few useful time expressions like this are:

• вранці = in the morning
• вдень = during the day / in the daytime
• увечері / ввечері = in the evening
• вночі = at night

Here, ввечері is an adverbial time expression, so you do not need a preposition like English in.

They are just variant forms of the same word, and both mean in the evening.

• увечері
• ввечері

The choice often depends on pronunciation flow and style. Ukrainian commonly alternates у / в to make speech sound smoother.

So in this sentence, пізно ввечері is completely normal.

They describe different things.

• зазвичай = usually
• спочатку = at first / first

So:

• зазвичай tells you how often this happens
• спочатку tells you the order of actions

зазвичай спочатку питає = usually first asks

In other words, when this situation happens, the person’s first reaction is to ask who is there.

Ukrainian often uses a singular verb with a generalizing subject like той, хто... because grammatically it means the one who...

So even though it refers to any person in general, the structure is singular:

• Той, хто чує..., питає...
• The one who hears..., asks...

English can also do this:

• Whoever hears it usually asks...

So the meaning is general, but the grammar is singular.

Yes. Ukrainian word order is flexible, though not completely free.

This version is natural:

• Той, хто чує дзвінок пізно ввечері, зазвичай спочатку питає, хто там.

But you could move adverbs around for emphasis, for example:

• Той, хто пізно ввечері чує дзвінок, зазвичай спочатку питає, хто там.
• Той, хто чує дзвінок, пізно ввечері зазвичай спочатку питає, хто там.
  (less neutral, more marked)

The original sentence sounds smooth and neutral.

Grammatically, inside the larger sentence it is an indirect question or a subordinate clause after питає.

• питає, хто там = asks who is there

But the words themselves are the same as in the direct question:

• Хто там? = Who’s there?

So Ukrainian does not need to change the word order the way English sometimes does in embedded questions. It simply uses:

• хто там

rather than something like хто є там. Ukrainian usually omits є (is) in the present tense in sentences like this.

Because in the present tense, Ukrainian often leaves out the verb бути (to be).

So:

• Хто там? literally looks like Who there?
• but it means Who is there?

This is very common:

• Він лікар. = He is a doctor.
• Хто там? = Who is there?

The missing is is just normal Ukrainian grammar, not an omission or mistake.