Jeg gad vide, om min søster tager sin guitar eller sin violin med i dag.

That is a very common question.

• gad is the past tense of gide
• gide often means something like feel like, be willing to, or bother to

But in the fixed expression jeg gad vide, Danish uses the past form idiomatically to mean:

• I wonder
• I’d like to know

So in this sentence, Jeg gad vide is best learned as a set phrase, not translated word-for-word.

A learner should think:

• Jeg gad vide ... = I wonder ...

Here om introduces an indirect yes/no question.

So:

• Jeg gad vide, om ... = I wonder whether / if ...

In this sentence, the speaker is wondering which instrument the sister is bringing, and om introduces that uncertainty.

Compare:

• Jeg ved ikke, om hun kommer. = I don’t know if she is coming.
• Jeg gad vide, om min søster tager sin guitar eller sin violin med i dag. = I wonder if my sister is bringing her guitar or her violin today.

So om here does not mean about. It means if / whether.

Because this is an indirect question, not a direct question.

In Danish:

• Direct questions often have inversion
  
  • Tager min søster sin guitar med i dag?
• Indirect questions keep normal statement word order
  
  • ... om min søster tager sin guitar med i dag

So after om, the clause behaves like a normal subordinate clause:

• subject: min søster
• verb: tager

This is very similar to English:

• Direct: Is my sister bringing her guitar today?
• Indirect: I wonder if my sister is bringing her guitar today.

This is one of the most important grammar points in the sentence.

Danish uses sin / sit / sine when the possessor refers back to the subject of the same clause.

Here, the subject is:

• min søster

And the possessed items are:

• sin guitar
• sin violin

That means the guitar and violin belong to the sister.

So:

• min søster tager sin guitar med = my sister brings her own guitar

If you said hendes guitar, it would usually mean:

• my sister brings some other female person’s guitar

So sin shows reflexive possession: the subject owns the thing.

No, sin is correct both times because both nouns are common gender singular nouns.

Danish reflexive possessives change according to the noun they belong to:

• sin = common gender singular
• sit = neuter singular
• sine = plural

Here:

• en guitar → common gender → sin guitar
• en violin → common gender → sin violin

Examples for comparison:

• Hun tager sin guitar med.
• Hun tager sit instrument med.
• Hun tager sine noder med.

Because tage med is a verb phrase, roughly meaning:

• take along
• bring

In Danish, particles like med are often separated from the main verb in a normal main clause.

So:

• Hun tager sin guitar med. = She brings her guitar.

This is similar to English phrasal verbs:

• take along
• bring along

You can think of tage ... med as a unit of meaning, even though the words are split in the sentence.

Because Danish often uses the present tense for actions in the near future, just like English does.

So:

• min søster tager ... med i dag can mean my sister is bringing ... today

It does not have to mean a habitual action. The time expression i dag makes it clear that the sentence is about today’s situation.

English does this too:

• She brings her violin today is less natural in English
• but She is bringing her violin today is natural

Danish often uses simple present where English would prefer present progressive.

Because the possessive already makes the noun definite.

In English:

• her guitar
• not usually the her guitar

In Danish:

• sin guitar
• sin violin

You do not add an article like en here.

So:

• sin guitar = her guitar
• sin violin = her violin

The possessive itself is enough.

Eller means or.

In this sentence, it links two alternatives:

• sin guitar
• sin violin

So the speaker is wondering which one the sister is bringing.

Structure:

• om min søster tager sin guitar eller sin violin med i dag

This means the choice is between those two things.

That is a very normal place for a time expression in Danish.

Danish often places adverbials like time expressions toward the end of the clause, especially after the object and after particles like med.

So this word order is natural:

• min søster tager sin guitar eller sin violin med i dag

You might sometimes see time expressions in other positions for emphasis, but the final position is neutral and common.

Yes. If you wanted to ask directly, you could say:

• Tager min søster sin guitar eller sin violin med i dag?

That means:

• Is my sister bringing her guitar or her violin today?

The original sentence is different because it expresses the speaker’s own uncertainty in an indirect way:

• Jeg gad vide, om ... = I wonder if ...

So the difference is mainly:

• direct question: asking openly
• indirect question: expressing wonder or curiosity

Yes, it is quite common and very natural.

It is a standard way to say:

• I wonder
• I’m curious to know

You may also hear related expressions such as:

• Jeg spekulerer på, om ... = I wonder if / I’m wondering whether ...

But Jeg gad vide is especially useful because it is short, idiomatic, and frequent in both speech and writing.

A helpful breakdown is:

• Jeg gad vide = main clause
• om = introduces an indirect question
• min søster = subject of the indirect clause
• tager ... med = verb phrase
• sin guitar eller sin violin = the alternatives / objects
• i dag = time expression

So the full structure is:

• I wonder
  • whether
    • my sister
      • is bringing
        • her guitar or her violin
          • today

This is a very useful sentence pattern to learn because you can reuse it easily:

• Jeg gad vide, om han kommer i morgen.
• Jeg gad vide, om de tager bilen med.
• Jeg gad vide, om hun har sine nøgler med.