Ja sada spremam sobu.

No. In Serbian, the verb form spremam already tells you the subject is I. So Spremam sobu is a complete sentence.

Adding ja is usually for emphasis, contrast, or clarity, for example:

• Ja sada spremam sobu, a on kuva. = I am tidying the room now, and he is cooking.

So in this sentence, ja is optional, not required.

Sada means now. Yes, sad is a very common shorter form, especially in everyday speech.

So these are both natural:

• Ja sada spremam sobu.
• Ja sad spremam sobu.

The longer sada can sound a little more careful or formal, while sad is very common in conversation.

Spremam is the 1st person singular present tense form of the verb spremati.

So:

• spremam = I tidy / I am tidying / I prepare / I am preparing, depending on context

The ending -am is the form for I with this verb.

Serbian does not form the present continuous the way English does. English uses am + verb-ing, but Serbian usually just uses the simple present tense.

So:

• Ja sada spremam sobu. = I am tidying the room now.

There is no separate word for am here, and no special -ing form. The present tense plus context, especially sada, gives the ongoing meaning.

Because sobu is in the accusative case.

The noun soba means room in the nominative form, which is the basic dictionary form. But here it is the direct object of the verb spremam, so Serbian uses the accusative:

• soba = nominative
• sobu = accusative

This is a very common pattern with feminine nouns ending in -a:

• knjiga → knjigu
• škola → školu
• soba → sobu

Yes. Serbian word order is more flexible than English word order because case endings and verb forms carry a lot of the grammar.

These are all possible:

• Ja sada spremam sobu.
• Sada spremam sobu.
• Spremam sobu sada.

They all mean roughly the same thing, but the emphasis changes slightly. The version you have is neutral and clear, especially for learners.

It most often suggests tidying up / putting the room in order.

Depending on context, spremati can also mean prepare or put away, so the exact nuance can vary. If you want to be more specifically about cleaning dirt or dust, Serbian often uses čistiti:

• Čistim sobu. = I am cleaning the room.
• Spremam sobu. = I am tidying / getting the room in order.

So spremam sobu is usually more like tidying the room than literally washing or dusting it.

Spremam comes from the imperfective verb spremati.

That matters because imperfective verbs are used for:

• actions in progress
• repeated actions
• general or ongoing situations

Since this sentence describes something happening now, the imperfective is the natural choice.

A related perfective verb is often spremiti, and in some contexts pospremiti can mean tidy up completely. Those forms are more about a completed action, while spremam focuses on the process.

Because Serbian does not have articles like a and the.

So sobu can mean:

• a room
• the room

The exact meaning comes from context. In a sentence like this, English usually translates it as the room, because that sounds most natural.

Yes, you can omit it.

• Ja sada spremam sobu. clearly means I am tidying the room now.
• Spremam sobu. can still mean I am tidying the room, but it can also mean something more general, like I tidy the room or I’m working on the room, depending on context.

So sada makes the right now meaning more explicit.