Ona danas ništa ne kupuje.

Yes, it could.

Serbian usually does not need a subject pronoun, because the verb ending already shows the person and number. Kupuje means he/she/it buys / is buying, so ona is often optional.

• Ona danas ništa ne kupuje. = She isn’t buying anything today.
• Danas ništa ne kupuje. = same basic meaning

Including ona can add a bit of emphasis or make it extra clear who you mean.

Danas means today.

Serbian word order is fairly flexible, so danas can appear in different places without changing the core meaning:

• Ona danas ništa ne kupuje.
• Danas ona ništa ne kupuje.
• Ona ništa ne kupuje danas.

These all mean roughly the same thing, but the emphasis can shift slightly depending on position.

Yes, from an English perspective it looks like a double negative, but in Serbian this is normal and required. This is called negative concord.

So in Serbian, if you use a negative word like ništa (nothing / anything in negative contexts), the verb also has to be negative:

• Ona ništa ne kupuje. = correct
• Ona ništa kupuje. = incorrect

English says She buys nothing or She doesn’t buy anything, but Serbian typically combines both parts of the negation:

• ništa
  • ne kupuje

Literally, ništa means nothing, but in English the most natural translation of the whole sentence is often:

• She isn’t buying anything today.

So depending on how you translate it, you may see:

• She is buying nothing today.
• She isn’t buying anything today.

Both match the Serbian sentence.

In Serbian, the negative particle ne is written separately from most verbs.

So:

• kupuje = she buys / is buying
• ne kupuje = she does not buy / is not buying

This is standard with most verbs:

• radi → ne radi
• govori → ne govori
• ide → ne ide

A few forms are exceptions, such as:

• nije = is not
• nemam = I do not have

But with kupuje, the correct form is two words: ne kupuje.

Kupuje is present tense, 3rd person singular, from kupovati.

It can correspond to different English present meanings depending on context:

• she buys
• she is buying
• sometimes even she has been buying in broader context, though less directly

With danas, the most natural English translation is usually:

• She isn’t buying anything today.

That sounds more like an action connected to today, not a general permanent fact.

This is about aspect, which is very important in Serbian.

• kupovati = imperfective
• kupiti = perfective

In the present tense:

• kupuje usually describes an ongoing, repeated, or general action
• kupi from kupiti usually does not mean a present ongoing action; with perfective verbs, the present often refers to the future

So:

• Ona danas ništa ne kupuje. = She isn’t buying anything today.
• Ona danas ništa ne kupi. would not normally be used this way

If you wanted a perfective future idea, you might say:

• Ona danas neće ništa kupiti. = She won’t buy anything today.

Kupuje is:

• 3rd person singular
• present tense
• from the verb kupovati (to buy, imperfective)

A quick mini-paradigm:

• ja kupujem = I buy / I am buying
• ti kupuješ = you buy / are buying
• on/ona/ono kupuje = he/she/it buys / is buying
• mi kupujemo
• vi kupujete
• oni/one/ona kupuju

So the form matches ona perfectly.

Yes. Ništa is the direct object of ne kupuje.

The sentence structure is basically:

• Ona = subject
• danas = time expression
• ništa = object
• ne kupuje = verb phrase

So literally:

• She today nothing not-buys

Of course, in natural English that becomes:

• She isn’t buying anything today.

Yes, absolutely.

That is also a correct Serbian sentence:

• Ona ne kupuje ništa danas.

It means the same thing. Serbian allows quite a lot of word-order variation. The differences are usually about emphasis, rhythm, or what sounds most natural in the moment, not about basic grammar.

Some common versions:

• Ona danas ništa ne kupuje.
• Ona danas ne kupuje ništa.
• Ona ne kupuje ništa danas.

All are valid.

In natural English, She isn’t buying anything today is usually the best translation.

That is because danas points to a specific time frame, and Serbian present tense often covers what English expresses with the present continuous.

So although Serbian uses a simple present form (kupuje), English often prefers:

• isn’t buying

rather than:

• doesn’t buy

The English simple present can sound habitual, while the Serbian sentence here most naturally refers to what she is doing today.

Ništa is pronounced roughly NEESH-ta.

A couple of useful points:

• š sounds like sh in shoe
• č / ć are not in this word, so don’t add a ch sound
• the i is a clear vowel, like ee in see, but shorter

So:

• ni ≈ nee
• šta ≈ shta

Together: NEESH-ta

Usually, with danas, listeners will understand it as specifically about today.

So the normal reading is:

• She isn’t buying anything today.

A habitual meaning is less likely here. If you wanted something like these days or lately, Serbian would usually use expressions such as:

• ovih dana = these days
• u poslednje vreme = lately / recently

So danas strongly points to today, not a general period.