Learn Hardcore Russian: Учитель повторил, что его просьба делать домашнее задание — не шутка. - The teacher repeated that his request to do homework is not a joke.

Учитель повторил, что… = The teacher repeated that…
The whole clause что его просьба делать домашнее задание — не шутка is the object of the verb повторил.

So the structure is:

Учитель повторил – main clause
что его просьба делать домашнее задание — не шутка – subordinate clause introduced by что (= that).

It is not a question word here.

Why is there a comma before что?

Russian usually puts a comma before conjunctions that introduce a subordinate clause.

повторил, что его просьба…

Here что introduces a content clause (what he repeated), so the comma is required by standard punctuation rules.

You will almost always see a comma before что when it connects two clauses like он сказал, что…, я думаю, что…, она знает, что…, etc.

Why is it повторил and not повторял? What is the difference?

The contrast is the usual Russian perfective vs imperfective aspect:

повторил – perfective, a single completed act:
- He repeated it (once / as a single event) and that’s the fact being reported.
повторял – imperfective, would suggest repeated or ongoing action:
- He used to repeat it / he was repeating it (over some period).

In this sentence, the speaker is narrating one concrete instance:
Учитель повторил, что… = The teacher (once again) repeated that…

So повторил fits better.

Why is it его просьба and not своя просьба? Don’t we usually use свой for one’s own things?

Both его просьба and своя просьба could be grammatically possible, but they are not fully equivalent.

его просьба = his request (neutral; just says his, may or may not be the subject’s own)
своя просьба = his own request (specifically tied to the subject of the clause)

Here, in the subordinate clause, the subject is его просьба, not the teacher:

что его просьба… — не шутка
- literal structure: that his request… is not a joke

There is no explicit subject referring to the teacher in this subclause, so using своя would be less natural. Свой normally refers back to the grammatical subject of the same clause.

Also, его просьба avoids ambiguity: it just clearly says his request (and from context we understand it’s the teacher’s).

What case is домашнее задание in, and why?

Домашнее задание is in the accusative singular neuter:

Dictionary form: домашнее задание (nom./acc. singular neuter)
After делать we need the direct object in the accusative.

In neuter -ое nouns, the nominative and accusative singular look the same, so the form doesn’t change, but its function here is object:

делать (что?) домашнее задание – to do (what?) homework.

Why is делать in the infinitive? Could it be something like делания домашнего задания instead?

The infinitive делать is used after the noun просьба to express what the request is about:

его просьба делать домашнее задание
- literally: his request (is) to do the homework

Russian often uses noun + infinitive combinations:

желание учиться – a desire to study
намерение поехать – an intention to go
просьба сделать – a request to do

Your alternative делания домашнего задания is a verbal noun phrase and feels very heavy, bookish, and unnatural in this everyday context. Native speakers would practically always say просьба делать домашнее задание (or просьба выполнять домашнее задание).

Why is it делать домашнее задание, not делать домашнюю работу or что‑то else for “homework”?

Several options exist in Russian:

домашнее задание – very common in the school context, literally home assignment.
домашняя работа – homework as “work done at home”; also correct, but in many classrooms домашнее задание is more standard.
домашка – colloquial, slangy: hw, homework (like “Did you do your hw?”).

So делать домашнее задание is the neutral, school-style phrase, which fits a teacher talking formally to students. Делать домашнюю работу would be understood, but the selected expression is more typical in this context.

Why is there a dash — before не шутка? Could I just put a verb there?

The dash here marks the link between the subject and the predicative (what the subject is):

его просьба … — не шутка
- его просьба = subject
- не шутка = predicative (saying what it is: not a joke)

In Russian, when both parts are nouns (especially with emphasis), a dash is common instead of a verb:

Москва — столица России. – Moscow is the capital of Russia.
Это — проблема. – This is a problem.

You could say:

его просьба делать домашнее задание — не шутка (as in the sentence)
его просьба делать домашнее задание — это не шутка (adds это, more explicit/emphatic)
его просьба делать домашнее задание не является шуткой (very formal, bookish).

The version with the dash is natural and neutral, and the omitted verb “is” is understood.

Why is there no word for “is”? Why not есть or является?

In present‑tense equative sentences (A is B), Russian usually drops the verb “to be”:

Он врач. – He is a doctor.
Это проблема. – This is a problem.
Его просьба — не шутка. – His request is not a joke.

Есть as “is/are” in such contexts is normally omitted.
Является can be used, but then the style becomes formal, official, or written:

Его просьба делать домашнее задание не является шуткой. – stylistically heavy.

The simple dash + no verb is the most natural choice here.

Could we say его просьба — делать домашнее задание, а не шутка? How does that change the meaning?

Yes, but it changes the structure and emphasis:

Его просьба делать домашнее задание — не шутка.
- Focus: The request itself (to do homework) is not a joke.
Его просьба — делать домашнее задание, а не шутка.
- Now делать домашнее задание is directly equated with его просьба:
  - His request is (for you) to do your homework, not a joke.

The original sentence highlights the seriousness of the request: it’s not meant as joking.
The alternative highlights what exactly the request is, then contrasts it with a joke in a slightly clumsier way. The original is smoother and more idiomatic.

Why is the subordinate clause in the present tense (его просьба … — не шутка) when the main verb is past (повторил)?

Because the teacher’s request is seen as currently valid at the time of speaking, not only in the past moment when he repeated it.

Main verb: повторил – he repeated (in the past).
Reported content: его просьба … — не шутка – his request is not a joke (this is presented as generally true / still true).

In Russian, the tense inside reported speech reflects the time of the situation itself, not just backshift from the reporting verb, similar to English:

English: He repeated that his request to do homework *is not a joke.*
(Present in the subordinate clause is also natural.)

Who does его refer to? Is it always the teacher here?

Formally, его just means his, and in isolation it could refer to any male person mentioned in context.

In this sentence, the only male person we have is учитель (the teacher), so by normal discourse logic, его is understood as the teacher’s.

If the broader context had another male person, you might need to clarify, for example:

Учитель повторил, что просьба Петра делать домашнее задание — не шутка.
- The teacher repeated that Pyotr’s request to do homework is not a joke.

But as the sentence stands, его просьба is interpreted as the teacher’s request.

How is повторил pronounced and stressed? Does stress change the meaning?

Повторил is pronounced with stress on the last syllable:

по‑вто‑рил

If you move the stress, it can sound wrong or like a different form:

повтóрил (stress on вто) would sound non‑standard / incorrect in modern Russian for this past‑tense masculine form.

Correct forms:

повтóрил – does not exist as a standard past form;
повтор (noun) – stress on ‑тор;
повторИл – past masc. sing. verb, which is our word here.

So you should say: Учитель повторИл, что….