Если во дворе слишком шумно, я закрываю окно.

In Russian, the verb to be is usually omitted in the present tense.

So:

• во дворе слишком шумно = it is too noisy in the courtyard
• literally, it is more like in the courtyard too noisy

This is very normal in Russian. Compare:

• Сейчас холодно. = It is cold now.
• В комнате тихо. = It is quiet in the room.

But in the past or future, forms of быть do appear:

• Во дворе было шумно. = It was noisy in the courtyard.
• Во дворе будет шумно. = It will be noisy in the courtyard.

There are two things happening here:

1. Location after в / во takes the prepositional case.

   • двор → дворе
   • So во дворе means in the yard / in the courtyard

2. Russian often uses во instead of в when pronunciation is easier that way.

   • во дворе sounds more natural than в дворе

Also, в/во + accusative would mean movement into something:

• во двор = into the yard
• во дворе = in the yard

So here, since the noise is located there, во дворе is correct.

Двор usually means a yard, courtyard, or the outdoor area around a building.

In this sentence, во дворе most naturally suggests something like:

• the courtyard of an apartment building
• the shared yard outside the house
• the area just outside where people are making noise

So it is not necessarily a private backyard in the English-speaking sense. In many Russian contexts, двор often refers to the common outdoor space around residential buildings.

Because шумно is not describing a noun directly. It describes the general situation: it is noisy.

Russian often uses words like this to describe states or conditions:

• шумно = noisy
• тихо = quiet
• холодно = cold
• темно = dark

So:

• Во дворе шумно. = It is noisy in the yard.

But if you describe a noun, then you use an adjective:

• шумный двор = a noisy yard
• шумная улица = a noisy street

So:

• шумно = the environment is noisy
• шумный / шумная / шумное = a noun is noisy

No. Слишком means too, in the sense of more than is acceptable or comfortable.

So:

• слишком шумно = too noisy
• очень шумно = very noisy

That difference matters. In this sentence, the speaker closes the window because the noise has crossed a limit. So слишком fits very well.

Закрываю is the imperfective form, and here it expresses a habitual or repeated action:

• Если во дворе слишком шумно, я закрываю окно.
• meaning: Whenever it is too noisy in the courtyard, I close the window.

This is a general rule or routine.

If you wanted to talk about one specific future situation, Russian would more likely use the perfective future:

• Если во дворе будет слишком шумно, я закрою окно.
• If it is too noisy in the courtyard, I will close the window.

So the difference is:

• закрываю = I do this regularly / as a general reaction
• закрою = I will do it once, in a specific future case

It is the direct object of закрываю, so it is in the accusative case.

However, окно is:

• singular
• neuter
• inanimate

For many neuter inanimate nouns, the accusative looks exactly the same as the nominative.

So:

• nominative: окно
• accusative: окно

That is why the form does not visibly change.

Compare with a noun that does change:

• машина → машину

So:

• Я вижу машину.
• but
• Я закрываю окно.

Yes. In Russian, a subordinate clause introduced by если is normally separated from the main clause by a comma.

So this is correct:

• Если во дворе слишком шумно, я закрываю окно.

And if you reverse the order, the comma is still used:

• Я закрываю окно, если во дворе слишком шумно.

This is a standard punctuation rule.

Yes. Russian word order is flexible.

You can say:

• Если во дворе слишком шумно, я закрываю окно.
• Я закрываю окно, если во дворе слишком шумно.

Both are correct.

The difference is mostly about emphasis and flow:

• starting with Если во дворе слишком шумно sets up the condition first
• starting with Я закрываю окно puts the main action first

The version in your sentence is very natural and common.

Often, yes. Russian frequently drops subject pronouns when the verb ending already makes the subject clear.

• закрываю already tells you it is I because of the ending

So you may hear:

• Если во дворе слишком шумно, закрываю окно.

However, keeping я is also completely normal. It can make the sentence a little clearer, more explicit, or slightly more emphatic.

So both are possible, but the version with я is perfectly standard.

Russian has no articles like a or the.

So окно can mean:

• a window
• the window

The exact meaning comes from context.

In this sentence, English naturally says the window because the speaker likely means a specific window in their room. Russian does not need a separate word for that; the context is enough.