Večeras ću biti kod moje sestre.

Večeras means tonight / this evening.

It is an adverb, so it answers when? In this sentence, it tells you when the speaker will be somewhere.

• večer / veče = evening (a noun)
• večeras = this evening / tonight (an adverb)

So Serbian uses večeras where English would naturally say tonight.

Ću biti is the future tense of biti (to be).

Serbian often forms the future with:

• a short form of hteti (to want, used as a future auxiliary)
• • the infinitive

So:

• ću = I will
• biti = be

Together:

• ću biti = I will be

In this sentence:

• Večeras ću biti... = Tonight I will be...

Both are possible in Serbian, but they are formed a little differently.

You can say:

• Večeras ću biti kod moje sestre.
• Večeras biću kod moje sestre.

However, ću biti is much more standard and natural in modern usage.

A useful learner rule:

• With most verbs, Serbian commonly uses ću + infinitive.
• With biti, you may also encounter fused forms like biću, but ću biti is very common and safe to use.

Because Serbian often omits subject pronouns when they are already clear from the verb.

Here, ću already tells you the subject is I.

So:

• Večeras ću biti kod moje sestre. = Tonight I will be at my sister’s place.

If you add ja, it becomes more emphatic:

• Ja ću večeras biti kod moje sestre. = I will be at my sister’s place.

So the pronoun is not necessary unless you want contrast or emphasis.

In this sentence, kod means something like:

• at
• at the place of
• over at
• with (in some contexts)

So kod moje sestre means at my sister’s place / at my sister’s home.

This is a very common Serbian structure:

• kod mame = at mom’s place
• kod doktora = at the doctor’s
• kod prijatelja = at a friend’s place

So kod often refers to someone’s place, not just physical proximity to the person.

Because kod requires the genitive case.

The basic form is:

• moja sestra = my sister (nominative)

After kod, it changes to genitive:

• kod moje sestre

Both words change:

• moja → moje
• sestra → sestre

So this is a normal case change caused by the preposition kod.

From both the meaning and the grammar.

The dictionary form is:

• moja sestra = my sister

After kod, Serbian uses the genitive. For a feminine singular noun like sestra, the genitive singular is:

• sestre

And the possessive adjective agrees with it:

• moja → moje

So:

• kod moje sestre = at my sister’s place

This is singular, not plural. If it were plural, the meaning would be at my sisters’ place, and the form would be different in context.

No, not for this meaning.

If you want to say at my sister’s place, Serbian uses kod + genitive:

• kod moje sestre

Using u would usually mean in or inside, or it would refer to being in a town, room, house, etc., not normally at someone’s place in this way.

Compare:

• kod moje sestre = at my sister’s place
• u kući moje sestre = in my sister’s house

So kod is the natural choice here.

Yes, Serbian word order is flexible, but some orders sound more natural than others.

The given sentence:

• Večeras ću biti kod moje sestre.

This is very natural.

You could also hear:

• Ću večeras biti kod moje sestre. — not natural as a standalone sentence
• Ja ću večeras biti kod moje sestre. — possible, with emphasis on I
• Kod moje sestre ću biti večeras. — possible, but emphasizes at my sister’s place
• Večeras ću kod moje sestre biti. — grammatical, but less natural

A key point is that ću is a clitic, and Serbian clitics tend to appear in the second position of the sentence or clause. That is why Večeras ću... sounds so natural.

Because ću is a clitic, and clitics in Serbian usually go in the second position in the sentence or clause.

In:

• Večeras ću biti kod moje sestre.

the first element is Večeras, so the clitic ću comes right after it.

If the sentence began with Ja, then the clitic would normally follow that:

• Ja ću biti kod moje sestre.

This second-position behavior is very important in Serbian and shows up with other short words too, such as:

• sam
• si
• je
• se
• mi
• ti

Not always with absolute certainty, but the usual meaning is at my sister’s place / at my sister’s home.

In many everyday contexts, it strongly suggests the speaker will be at her place. Depending on context, it can sometimes also be understood more loosely as with my sister.

Still, if you translate it naturally, at my sister’s place is usually the best choice.

It can mean both, depending on context.

In English:

• this evening may sound a bit earlier or more formal
• tonight is often the most natural everyday translation

So:

• Večeras ću biti kod moje sestre. can be translated as either:
• Tonight I’ll be at my sister’s place.
• This evening I’ll be at my sister’s place.

In most casual contexts, tonight is probably the most natural English equivalent.

Yes. In everyday speech, you might hear slightly different wordings, for example:

• Večeras ću biti kod sestre.
• Večeras sam kod sestre. — if the future is understood from context, though this is more context-dependent
• Večeras idem kod sestre. = Tonight I’m going to my sister’s place

But the original sentence:

• Večeras ću biti kod moje sestre.

is perfectly correct, clear, and natural. It may sound a little more explicit because it includes both ću biti and moje.