Choć mój pokój jest mały, lubię w nim czytać.

Choć means although, though, or even though.

In this sentence, it introduces a contrast:

Choć mój pokój jest mały, lubię w nim czytać.
= Although my room is small, I like reading in it.

It is completely normal and natural in everyday Polish. A very close alternative is chociaż, which means the same thing. Choć is simply shorter.

In Polish, a clause introduced by choć is normally separated by a comma from the main clause.

So the sentence has two parts:

• Choć mój pokój jest mały = although my room is small
• lubię w nim czytać = I like reading in it

That is why the comma appears between them.

Because pokój is a masculine singular noun, and the possessive adjective mój has to agree with it.

Polish adjectives and possessive words change to match the noun’s:

• gender
• number
• case

So:

• mój pokój = my room
• moja książka = my book
• moje okno = my window

Since pokój is masculine singular, mój is the correct form.

Yes. Mały agrees with pokój in gender, number, and case.

Here:

• pokój is masculine singular
• it is the subject of the clause
• so it is in the nominative case

That gives:

• pokój jest mały = the room is small

Compare:

• pokój jest mały = the room is small
• książka jest mała = the book is small
• okno jest małe = the window is small

Nim is the form of on / it used after the preposition w.

Here, nim refers back to pokój:

• w nim = in it
• literally: in the room

So:

lubię w nim czytać = I like reading in it

Because pokój is masculine, the pronoun form is based on masculine/neuter on / ono, and after w, the form becomes nim.

You could say w pokoju, and it would be correct:

Choć mój pokój jest mały, lubię czytać w pokoju.

But that sounds less natural here, because it repeats pokój unnecessarily. Polish, like English, often uses a pronoun to avoid repetition.

So w nim is a natural way to say in it after already mentioning pokój.

Because prepositions in Polish require specific cases.

The preposition w can take different cases depending on meaning:

• w + locative = in somewhere, location
• w + accusative = movement into something, in some special contexts

Here the meaning is location: reading in the room, so Polish uses the locative.

That is why:

• w nim = in it

not:

• w niego

Also, on is the basic dictionary form of the pronoun, but after prepositions you usually need a changed form, such as nim.

After lubić when you mean to like doing something, Polish normally uses the infinitive.

So:

• lubię czytać = I like to read / I like reading
• lubię pływać = I like to swim
• lubię gotować = I like to cook

Using czytam would mean I am reading / I read, which is a finite verb form, and it does not fit after lubię in this structure.

Because the sentence describes a general, habitual activity: I like reading in it.

In Polish, the imperfective verb is usually used for:

• general activities
• repeated actions
• ongoing processes

So czytać is the natural choice.

A perfective verb would suggest a completed action, which would not fit well after lubię in this general sense.

Yes, Polish word order is more flexible than English word order.

The given sentence is natural:

Choć mój pokój jest mały, lubię w nim czytać.

You could also hear:

• Choć mój pokój jest mały, lubię czytać w nim.

Both are correct. The difference is mostly one of emphasis and rhythm.

• lubię w nim czytać slightly highlights in it
• lubię czytać w nim puts czytać closer to lubię, which may feel a bit more neutral to some speakers

Both are good Polish.

Grammatically, nim can correspond to him or it, depending on what noun it refers to.

Here it refers to pokój = room, so in English we translate it as it:

• w nim = in it

Even though pokój is grammatically masculine in Polish, that does not mean it is he in English. It is still just it.

A natural translation would be:

Although my room is small, I like reading in it.

Other natural versions are:

• Though my room is small, I like reading in it.
• Even though my room is small, I like to read in it.

All of these match the Polish sentence well.

Choć is pronounced approximately like hohch, but the final sound is soft and does not have a perfect English equivalent.

A rough guide:

• ch in Polish is like a throaty h sound
• o is like o in off or or depending on accent
• ć is a soft sound somewhat like ch in cheek, but lighter and more palatal

So a rough learner-friendly approximation is:

choć ≈ hohch

But it is best to listen to native audio, because the final ć is hard to capture with English spelling.