Сегодня сестра хочет на балет, а брат — на мюзикл.

Russian often leaves out a verb like идти / пойти when it is easy to understand from context.

So:

• Сестра хочет на балет = The sister wants to go to the ballet
• Full version: Сестра хочет пойти на балет

This omission is very common in everyday Russian, especially with places or events after хотеть.

Because in Russian, when you mean going to an event, you usually use на + accusative.

Examples:

• на балет = to the ballet
• на концерт = to the concert
• на спектакль = to the play
• на мюзикл = to the musical

This is different from going to a place/building, which often uses в:

• в театр = to the theater
• в школу = to school

So:

• идти в театр = go to the theater building
• идти на балет = go to a ballet performance

Yes. After на in the meaning of motion toward an event, Russian uses the accusative case.

Here:

• балет is masculine, inanimate
• мюзикл is masculine, inanimate

For masculine inanimate nouns, the accusative singular is the same as the nominative singular. So the forms do not change:

• балет → на балет
• мюзикл → на мюзикл

That is why you do not see a different ending here.

In this sentence, а shows a contrast of topics:

• Today, the sister wants to go to the ballet, while the brother wants to go to a musical.

It does not mean a strong contradiction like but in all cases. Very often, а means something like:

• while
• whereas
• and as for...

Compare:

• и = simple and
• но = stronger but
• а = contrast or comparison between two things

So а is the most natural choice here because the sentence compares the sister’s preference with the brother’s.

The dash shows that a word has been omitted because it is understood from the first part.

Full version:

• Сегодня сестра хочет на балет, а брат хочет на мюзикл.

Russian often leaves out repeated words, especially verbs, to avoid sounding repetitive. The dash marks that omission.

So:

• брат — на мюзикл really means брат хочет на мюзикл

This is very natural in written Russian.

Yes, absolutely.

Both are correct:

• Сегодня сестра хочет на балет, а брат — на мюзикл.
• Сегодня сестра хочет на балет, а брат хочет на мюзикл.

The version with the dash is a little more compact and stylistically smoother because it avoids repeating хочет.

Yes, Russian word order is flexible.

Сегодня at the beginning sets the time frame for the whole sentence:

• Сегодня сестра хочет на балет, а брат — на мюзикл.

But other word orders are also possible, depending on emphasis:

• Сестра сегодня хочет на балет, а брат — на мюзикл.
• Сестра хочет сегодня на балет, а брат — на мюзикл.

The sentence you have is natural because it begins with the time word and frames the whole situation as today.

Russian has no articles.

So nouns like:

• сестра
• брат
• балет
• мюзикл

can mean the sister / a sister, the brother / a brother, depending on context.

English must choose between the, a, or zero article, but Russian does not mark that grammatically.

The exact meaning comes from context.

Literally, хочет just means wants.

But because it is followed by на балет / на мюзикл, the understood meaning is:

• wants to go to the ballet
• wants to go to the musical

So the idea of going is implied rather than directly stated.

This is very common in Russian and sounds natural.

Not in this meaning.

If you want to say wants to go to the ballet, you need:

• хочет на балет
• or хочет пойти на балет

Without на, хочет балет would sound incomplete or unnatural in this context, because балет is an event you go to, not just a thing you directly "want" in the same way.

Yes, мюзикл is a normal Russian noun borrowed from English musical.

It does decline like a regular masculine inanimate noun:

• мюзикл — nominative
• мюзикла — genitive
• мюзиклу — dative
• мюзикл — accusative
• мюзиклом — instrumental
• о мюзикле — prepositional

In this sentence, it stays мюзикл because the accusative of an inanimate masculine noun matches the nominative.

It is natural standard Russian, but the omission in хочет на балет and especially the dash in а брат — на мюзикл make it feel a bit more compact and conversational-stylish.

You could make it more explicit:

• Сегодня сестра хочет пойти на балет, а брат хочет пойти на мюзикл.

That version is fuller and clearer for a learner, but native speakers often prefer the shorter version when the meaning is obvious.