Sutra nosim pasoš sa sobom, jer putujem vozom.

In Serbian, the present tense is very often used for a planned or scheduled future action, especially when a time word like sutra already makes the future meaning clear.

So:

• Sutra nosim pasoš sa sobom = Tomorrow I’m taking my passport with me
• jer putujem vozom = because I’m traveling by train

This sounds natural in Serbian, much like English can say Tomorrow I’m leaving.

A more explicitly future version is also possible:

• Sutra ću nositi pasoš sa sobom, jer ću putovati vozom.

But in everyday Serbian, the present tense with sutra is very common.

Because pasoš is the direct object of nosim (I carry / I take), and direct objects usually go in the accusative case.

For a masculine inanimate noun like pasoš, the accusative singular is the same as the nominative singular:

• nominative: pasoš
• accusative: pasoš

So:

• Nosim pasoš = I’m carrying a passport / the passport

If it were a masculine animate noun, the accusative would usually look different.

Sa sobom means with oneself / with me / with him / with her, depending on the subject.

In this sentence, the subject is I (understood from nosim and putujem), so sa sobom means:

• with me

Literally, though, Serbian uses the reflexive form:

• sa = with
• sobom = oneself (instrumental case of sebe)

So nosim pasoš sa sobom is literally something like:

• I carry the passport with myself

but in natural English:

• I’m taking my passport with me

Because Serbian uses the reflexive pronoun when the object refers back to the subject.

Here, the person carrying the passport and the person the passport is with are the same person. So Serbian prefers:

• sa sobom = with oneself / with me (when the subject is I)

Compare:

• Nosim pasoš sa sobom. = I’m taking my passport with me.
• Nosim pasoš sa njim. = I’m taking the passport with him.
• Nosim pasoš sa njom. = I’m taking the passport with her.

So sobom shows that it refers back to the subject.

Because the verb here uses the phrase sa + instrumental to mean with someone or something.

So you need the preposition:

• sa sobom = with oneself / with me

Without sa, sobom would not work naturally here.

Because Serbian often uses the instrumental case without a preposition to express the means of transport.

So:

• putujem vozom = I travel by train
• idem autobusom = I go by bus
• putujemo avionom = we travel by plane

Here:

• nominative: voz = train
• instrumental: vozom = by train

So vozom is the correct form after putujem when you mean the mode of transport.

Normally, no. If you mean by train, Serbian uses the instrumental without a preposition:

• putujem vozom

Using sa vozom would sound wrong for means of transport in this context.

Think of it this way:

• vozom = by train
• sa vozom would literally suggest with the train, which is not how Serbian expresses transportation method here.

Because jer means because and introduces a subordinate clause.

The sentence has two parts:

• Sutra nosim pasoš sa sobom
• jer putujem vozom

In standard Serbian spelling, a clause introduced by jer is separated with a comma.

So the comma is normal and expected here.

Yes. Serbian word order is fairly flexible, although some versions sound more natural than others depending on emphasis.

The original:

• Sutra nosim pasoš sa sobom, jer putujem vozom.

Other possible orders include:

• Nosim sutra pasoš sa sobom, jer putujem vozom.
• Pasoš nosim sa sobom sutra, jer putujem vozom.
• Jer putujem vozom, sutra nosim pasoš sa sobom.

These all shift emphasis a little:

• Sutra at the beginning emphasizes tomorrow
• Pasoš at the beginning emphasizes the passport
• Jer putujem vozom first emphasizes the reason

The original sentence is very natural and neutral.

Both s and sa can mean with, but sa is often used for easier pronunciation, especially before certain consonant combinations.

Since sobom begins with s, Serbian normally uses:

• sa sobom

This is the standard and natural form here.

They are similar, but not exactly the same.

• nosim pasoš sa sobom focuses on having/carrying/taking it along
• uzimam pasoš sa sobom focuses more on taking it with me at the moment of departure

In many situations both are understandable, but nosim pasoš sa sobom is very natural for saying that you will have the passport with you.

Serbian often leaves out possessive words like my, your, or his when the meaning is already obvious from context.

So:

• Nosim pasoš sa sobom naturally implies I’m taking my passport with me

If you want to be extra explicit, you can say:

• Nosim svoj pasoš sa sobom.

But in this sentence, svoj is not necessary.

The dictionary forms are:

• nositi = to carry, to wear, to take along
• putovati = to travel

The forms in the sentence are:

• nosim = I carry / I am carrying / I’m taking
• putujem = I travel / I am traveling

Both are 1st person singular present tense forms.