В подъезде темно, поэтому я включаю маленький фонарик.

Not exactly. In Russian, подъезд often means the entrance area / stairwell / entryway of an apartment building—the shared space you go into before reaching the apartments.

So in this sentence, В подъезде темно is more like:

• It’s dark in the building entrance
• It’s dark in the stairwell
• It’s dark in the entryway

A native English speaker might first think of entrance in a general sense, but подъезд is a very common Russian word for that specific apartment-building area.

Because в can be followed by different cases depending on the meaning:

• в + accusative = motion into something
• в + prepositional = location in something

Here the sentence describes location, not movement:

• в подъезде = in the entrance / in the stairwell

Compare:

• Я иду в подъезд. = I’m going into the entrance.
• Я стою в подъезде. = I’m standing in the entrance.

So подъезде is the prepositional case form of подъезд.

This is the regular prepositional singular ending for many masculine nouns.

Dictionary form:

• подъезд

Prepositional singular:

• в подъезде

This is a common pattern:

• дом → в доме
• город → в городе
• подъезд → в подъезде

So the ending -е tells you the noun is in the prepositional case after в when expressing location.

Because темно here is not an adjective describing a noun. It is a state word (sometimes called a predicative adverb), meaning it is dark.

Russian often uses these words to describe general conditions:

• темно = it is dark
• холодно = it is cold
• жарко = it is hot
• тихо = it is quiet

So:

• В подъезде темно. = It’s dark in the entrance.

If you used тёмный, that would usually describe a noun:

• тёмный подъезд = a dark entrance
• тёмная комната = a dark room

But here the sentence is not saying the entrance is a dark one as a descriptive label; it is stating the current condition: it’s dark.

Because Russian does not need a dummy subject like English it in sentences such as:

• It is dark
• It is cold
• It is late

In Russian, you simply say:

• Темно.
• Холодно.
• Поздно.

So В подъезде темно is literally more like In the entrance, dark, but naturally it means It’s dark in the entrance.

Поэтому means therefore, that’s why, or so.

In this sentence:

• В подъезде темно, поэтому я включаю маленький фонарик.
• It’s dark in the entrance, so I turn on a small flashlight.

It often appears after the first clause and introduces the result or consequence.

A very common pattern is:

• [reason], поэтому [result]

For example:

• Я устал, поэтому я иду домой.
  I’m tired, so I’m going home.

Because поэтому is linking two clauses:

• В подъезде темно
• я включаю маленький фонарик

In standard Russian punctuation, when поэтому connects clauses like this, it is typically preceded by a comma.

So the structure is:

• [Clause 1], поэтому [Clause 2].

This is very normal and something you will see often in written Russian.

This is an aspect question.

• включать → imperfective
• включить → perfective

Here, включаю is the 1st person singular present of the imperfective verb включать.

Why use imperfective here? A few possible reasons:

1. Present-time narration
   The speaker is describing what they do in this situation:

   • It’s dark, so I turn on a flashlight.

2. Habitual/repeated action
   This can imply something like:

   • Whenever it’s dark there, I turn on a small flashlight.

3. Focus on the action/process rather than completion
   The sentence presents the act itself, not the completed result.

If you said включу, that would be perfective future:

• I will turn on

So:

• я включаю = I turn on / I am turning on
• я включу = I will turn on

Yes. The imperfective present can describe an action happening right now, especially in context.

So я включаю маленький фонарик can mean:

• I’m turning on a small flashlight
• I turn on a small flashlight

Russian present tense often covers both the English simple present and present continuous, depending on context.

It is in the accusative case, because it is the direct object of включаю.

However, for masculine inanimate singular nouns, the accusative looks the same as the nominative.

So:

• nominative: маленький фонарик
• accusative: маленький фонарик

That is why it looks unchanged.

Compare with a feminine noun, where the accusative would look different:

• маленькая лампа → маленькую лампу

So the object does take accusative here; it just happens to have the same form.

Because маленький agrees with фонарик:

• фонарик is masculine
• singular
• inanimate
• here it is in the accusative, which for masculine inanimate matches the nominative

So the adjective must match that form:

• маленький фонарик

This is adjective-noun agreement in gender, number, and case.

Yes, here фонарик means flashlight or small torch.

It is also a diminutive form of фонарь.

• фонарь = lamp, lantern, streetlight, flashlight (depending on context)
• фонарик = little flashlight / small torch

In everyday speech, фонарик is very natural for a small handheld light.

The diminutive does not always sound especially emotional in Russian. Often it just refers to something small or is the normal everyday word.

You could, but it would sound less natural in many everyday situations.

For a handheld flashlight, Russians very often say фонарик. It is the usual word in many contexts.

So:

• фонарик = very natural for a small flashlight
• фонарь = a broader word, and can also mean things like a lantern or street lamp depending on context

That is why маленький фонарик sounds especially natural here.

Yes, Russian can often omit subject pronouns when the verb ending already makes the subject clear.

So both are possible:

• ... поэтому я включаю маленький фонарик.
• ... поэтому включаю маленький фонарик.

The version with я is a bit more explicit and can add slight emphasis or clarity.

Since включаю already clearly means I turn on / I am turning on, the pronoun is not strictly necessary.

The main stresses are:

• в подъе́зде
• темно́
• поэ́тому
• включа́ю
• ма́ленький
• фона́рик

Stress is important in Russian, especially for pronunciation and vowel reduction. For example:

• подъе́зд
• в подъе́зде

The stress stays on е́ there.