Learn Hardcore Croatian: Moja sestra svira gitaru, a brat svira klavir. - My sister plays the guitar, and my brother plays the piano.

On svira klavir. – He plays the piano. (klavir is accusative = same as nominative for many masculine nouns)
On svira gitaru. – He plays the guitar. (gitaru accusative, feminine)

Why is brat not also preceded by moj (why not a moj brat svira klavir)?

It can be:

Moja sestra svira gitaru, a moj brat svira klavir.

However, in Croatian it’s very natural to omit repeated possessives when the context is clear, especially with close family members.

Because the sentence already starts with Moja sestra (my sister), the listener easily understands that brat is also “my brother,” so you don’t need to repeat moj.

Both versions are correct:

With moj: slightly more explicit.
Without moj: more natural, less repetitive.

Why is there no word for she or he (like ona or on)?

Croatian is a pro‑drop language: subject pronouns (ja, ti, on, ona, mi, vi, oni...) are usually omitted when the verb form already shows who is doing the action.

In Moja sestra svira gitaru:

The subject is clearly moja sestra (my sister).
Adding ona would be redundant: Ona, moja sestra, svira gitaru – possible, but normally unnecessary and stylistically heavier.

So Croatian usually skips he/she unless:

You need to emphasise the subject.
Or you want to contrast people: On svira klavir, a ona gitaru. – He plays piano, and she (plays) guitar.

Does svira mean specifically “play a musical instrument”?

Yes. Svirati means to play (a musical instrument).

You use it for things like:

svirati gitaru – to play the guitar
svirati klavir – to play the piano
svirati violinu – to play the violin

You do not use svirati for:

Playing sports → igrati (e.g. igrati nogomet – to play football)
Playing general games → often igrati se or igrati.

So svira gitaru is exactly “plays (the) guitar”, musically.

Why is svira the same for both sestra and brat?

In Croatian, verbs in the present tense change by person and number, not by gender.

Svirati – present tense (singular):

(ja) sviram – I play
(ti) sviraš – you (sg.) play
(on / ona / ono) svira – he / she / it plays

Both moja sestra and brat are third person singular (ona / on), so they both take the same verb form: svira.

Moja sestra svira gitaru. – She plays the guitar.
Brat svira klavir. – He plays the piano.

What is the difference between a and i? Both can look like and in English.

Both a and i can be translated as and, but they have different nuances.

i = simple and, just adding information.
- Imam sestru i brata. – I have a sister and a brother.
a = often and / but / while, used to show contrast or difference, or to place two things side by side for comparison.

In Moja sestra svira gitaru, a brat svira klavir:

a suggests a kind of contrast: My sister plays the guitar, while my brother plays the piano.

If you said:

Moja sestra svira gitaru i brat svira klavir.
it would sound less natural and miss that contrastive “one does X, the other does Y” feeling.

Could I say Moja sestra svira gitaru, a brat klavir (omit the second svira)?

Yes, that’s possible and quite natural in spoken and informal written Croatian.

Moja sestra svira gitaru, a brat klavir.

The second svira is understood from context. This is a kind of ellipsis (omitting repeated words when they are obvious).

All of these are acceptable, with slightly different styles:

Moja sestra svira gitaru, a brat svira klavir. (full, explicit)
Moja sestra svira gitaru, a brat klavir. (shorter, more fluent)

Could I change the word order, like Gitaru svira moja sestra?

Yes. Croatian word order is more flexible than English because cases show the grammatical roles.

All of these are grammatically correct, but have different emphasis:

Moja sestra svira gitaru. – neutral: My sister plays the guitar.
Gitaru svira moja sestra. – emphasises gitaru or a contrast: It’s the guitar that my sister plays.
Moja sestra gitaru svira. – possible, but marked/poetic or used for strong emphasis.

For beginners, it’s best to stick to the neutral SVO order:

Moja sestra svira gitaru.

Why is there no equivalent of the in svira gitaru and svira klavir?

Croatian has no articles (the, a, an). Nouns appear without them, and you interpret definiteness from context.

svira gitaru can mean:
- plays the guitar
- plays a guitar
  depending on the situation.

With instruments and some other nouns, English often uses the, but Croatian just uses the bare noun in the right case:

svira gitaru – plays (the) guitar
svira klavir – plays (the) piano

Why is the instrument in accusative with svirati? Could I also say svirati na gitari?

With svirati and a specific instrument, Croatian usually uses the instrument as a direct object in the accusative case:

svirati gitaru – to play the guitar
svirati klavir – to play the piano
svirati violinu – to play the violin

This focuses on what you play.

You can also say:

svirati na gitari – literally “to play on the guitar”.

This can sound a bit more descriptive, like focusing on the instrument as a surface/medium, and is often used in some styles or contexts, but svirati gitaru is the default and more common when simply stating that someone plays that instrument.

So in this sentence, svira gitaru and svira klavir are the most natural choices.