Ona pjeva kao da je u kazalištu, i u sobi više nije tišina.

In Croatian the subject pronoun ona is usually optional, because the verb ending -a in pjeva already tells you it’s she (3rd person singular).

• Ona pjeva kao da je u kazalištu. – fully correct, slightly more explicit/emphatic.
• Pjeva kao da je u kazalištu. – also fully correct and very natural.

Use ona if you want to:

• contrast with someone else (Ona pjeva, a on šuti. – She sings, and he is silent.), or
• reintroduce or stress the subject.

Otherwise, it’s often dropped in everyday speech and writing.

Pjeva is the 3rd person singular present tense of pjevati (to sing), an imperfective verb.

• Ona pjeva = She is singing / She sings (Croatian uses the same present for both “is singing” and “sings”).
• Imperfective aspect here emphasizes an ongoing, repeated, or habitual action, not a finished one.

A perfective partner would be otpjevati (to sing something through / finish singing), e.g. Ona je otpjevala pjesmu – She sang/has sung the song (to the end).

• kao = like / as

  • Pjeva kao slavuj. – She sings like a nightingale.

• kao da = as if / as though and is normally followed by a clause with a verb:

  • Pjeva kao da je u kazalištu. – She sings as if she were in a theater.

So:

• kao + noun/adjective/adverb
• kao da + full clause (with a verb)

In your sentence, kao da je u kazalištu is a full clause (as if she is in the theatre), so kao da is the right choice.

Croatian is more flexible than English here:

• kao da je u kazalištu
• kao da bi bila u kazalištu

Both are grammatically correct, but their feel is different:

1. kao da je u kazalištu (indicative je)

   • Very common in modern speech.
   • Can sound more vivid / realistic, as if the situation is quite believable or almost real.
   • Often used even when the speaker knows it’s not literally true.

2. kao da bi bila u kazalištu (conditional bi bila)

   • Sounds more clearly hypothetical or counterfactual, closer to English “as if she were in a theater.”
   • Slightly more formal / heavier; often used when you want to stress the unreality.

In everyday language, people very often say kao da je u kazalištu even when they mean it metaphorically, as in your sentence.

kazalištu is in the locative singular (neuter noun kazalište, “theater”).

• Preposition u
  • locative is used to express location where something is:
    • u kazalištu – in the theater
    • u sobi – in the room
    • u gradu – in the city

So u kazalištu literally means in (the) theater as a place.

• kazalište – theater (BrE) / theatre (AmE “theater”), especially as an institution or building for plays, opera, etc.
• teatar – also “theater”, borrowed from French/Latin, often a bit more “artsy” or used in names of theaters, styles, etc.

In standard Croatian:

• kazalište is the more neutral, common word.
• teatar is very common too, but can carry a slightly more “artistic” or foreign feel depending on context.

In your sentence, kazalište is perfectly standard and natural.

i usually means “and”, but it also often has a nuance of “and now also / and as a result”.

Here, i links the effect of her singing to the previous clause:

• Ona pjeva kao da je u kazalištu, i u sobi više nije tišina.
  – She sings as if she were in a theater, and (as a result) there is no longer silence in the room.

So i is joining two clauses and slightly emphasizes that the second one follows naturally from the first.

In Croatian, the comma before i is used when it joins two independent clauses (two full sentences):

• Ona pjeva kao da je u kazalištu, i u sobi više nije tišina.
  
  1. Ona pjeva kao da je u kazalištu.
  2. U sobi više nije tišina.

Because each part could stand as its own sentence, a comma is acceptable.

You may also see it without a comma in everyday writing:

• Ona pjeva kao da je u kazalištu i u sobi više nije tišina.

Style guides vary a bit; many recommend no comma when the clauses share the same subject and are closely linked, but using the comma is not wrong and can give a slight pause/emphasis.

Literally:

• više – anymore / no longer
• nije – is not (3rd sg neg. of biti, “to be”)
• tišina – silence

So više nije tišina is:

• it is no longer silence
• there is no longer silence

The implied structure is something like (Tamo) više nije tišina – It is no longer silence (there). In natural English, we make it existential: There is no longer silence (in the room).

Both are possible, but they’re slightly different structures:

1. nije tišina – uses the verb biti (to be)

   • Treats tišina as a state that exists or not:
     
     • U sobi je tišina. – There is silence in the room.
     • U sobi više nije tišina. – There is no longer silence in the room.

2. nema tišine – uses nemati (to not have / there not to be)

   • Focuses on lack/absence of something:
     
     • U sobi nema tišine. – There is no silence in the room / The room lacks silence.

In your sentence, više nije tišina sounds more like a change of state: it was silent, but now it is not silence anymore.
Nema tišine would shift the focus slightly more to “there is not any silence (at all).”

Yes, you could say:

• U sobi više nije tiho. – It is no longer quiet in the room.

Differences:

• nije tišina – uses the noun “silence”, a bit more “dramatic” or “poetic”:
  
  • Emphasis on the state of silence no longer being present.
• nije tiho – uses the adjective/adverb “quiet”:
  
  • More neutral, everyday way to say it’s not quiet anymore.

Both are correct; the original with tišina is slightly more expressive.

sobi is in the locative singular (feminine noun soba, “room”).

• u sobi – in the room
• u kazalištu – in the theater

Both use u + locative to express location where something is happening. Only the noun endings differ because soba is feminine and kazalište is neuter.

Croatian word order is relatively flexible, and you can move elements to change focus:

• U sobi više nije tišina. – neutral/default: In the room, there is no longer silence.
• Više u sobi nije tišina. – emphasizes više (“no longer”), a bit more dramatic.
• U sobi tišina više nije. – stylistically marked, almost poetic.

All can be understood, but the given version u sobi više nije tišina is the most neutral and natural in everyday language.