Learn Hardcore Greek: Η αδερφή μου δουλεύει καλύτερα με μουσική· εγώ, αντίθετα, θέλω σιωπή. - My sister works better with music; I, on the contrary, want silence.

αδερφή is the more colloquial, everyday spelling and matches how most people actually pronounce the word.
αδελφή is more traditional / conservative and is what you often see in more formal or older texts (and in dictionaries as the “base” form αδελφός, -ή, -ό).

In modern usage, αδερφή μου is completely standard and natural in speech and informal writing.

Why is μου placed after αδερφή and not before, like μου αδερφή?

In Greek, the unstressed possessive pronouns (μου, σου, του, της, μας, σας, τους) normally come after the noun:

η αδερφή μου = my sister
το βιβλίο σου = your book

Putting μου before the noun (μου αδερφή) is wrong in standard Greek.
If you want to stress the possessor, you can add the stressed form in front, but you still keep μου after the noun:

η δική μου αδερφή = my (own) sister (with emphasis on my)

What tense is δουλεύει, and does it mean works or is working?

Δουλεύει is the present tense, third person singular of δουλεύω (to work).

Greek present tense covers both English simple present and present continuous. So δουλεύει can mean:

she works (in general)
she is working (right now / usually, etc.)

In your sentence, it has a general meaning: My sister works better with music.

What exactly does καλύτερα mean, and how is it different from καλά or πιο καλά?

Καλύτερα is the comparative adverb of καλά (well).

καλά = well
- δουλεύει καλά = she works well
καλύτερα = better
- δουλεύει καλύτερα = she works better

You can also say πιο καλά for better; it’s very common in speech:

δουλεύει πιο καλά (με μουσική) = she works better (with music)

So καλύτερα and πιο καλά are usually interchangeable in everyday Greek. Καλύτερα is a bit more compact and slightly more “standard.”

Why is it με μουσική and not με τη μουσική? When do you drop the article?

Here με μουσική means with (some) music / with music in general, not with some specific, identified piece of music.

Greek often omits the article with uncountable or abstract nouns when you mean them in a general way:

πίνω καφέ = I drink coffee (in general), not τον καφέ
δουλεύω με μουσική = I work with music (in general), not με τη μουσική

If you say με τη μουσική, it sounds more like with the music (that specific music we both know about), which is not what is meant here.

What is the raised dot · in the middle of the sentence? Is it like a semicolon?

That symbol · is called άνω τελεία (ano teleia) in Greek.

Functionally, it is closest to the semicolon or a stronger comma in English. It separates two related clauses more clearly than a normal comma, but less finally than a full stop.

So:

Η αδερφή μου δουλεύει καλύτερα με μουσική· εγώ, αντίθετα, θέλω σιωπή.
≈ My sister works better with music; I, on the other hand, want silence.

Why is εγώ written explicitly here? I thought Greek usually drops subject pronouns.

Greek can drop subject pronouns because the verb ending shows the person. But pronouns like εγώ are used when you want to emphasize or contrast the subject.

Here the contrast is between η αδερφή μου and εγώ:

Η αδερφή μου δουλεύει καλύτερα με μουσική· εγώ, αντίθετα, θέλω σιωπή.
= My sister works better with music; I, on the contrary, want silence.

If you dropped εγώ (…· αντίθετα, θέλω σιωπή), the meaning would still be understandable, but you’d lose some of the clear contrast and emphasis on I.

What does αντίθετα mean here, and where can it go in the sentence?

Αντίθετα literally comes from αντίθετος = opposite. As an adverb here, it means on the contrary / in contrast / on the other hand.

Common positions in this sentence would be:

εγώ, αντίθετα, θέλω σιωπή. (as in your example)
εγώ αντίθετα θέλω σιωπή. (without the second comma, also used)
αντίθετα, εγώ θέλω σιωπή. (putting the contrast word at the start)

All three sound natural. The version with commas around αντίθετα highlights it as a parenthetical, much like “I, on the other hand, want silence.”

Why are there commas around εγώ and αντίθετα? Could I leave them out?

The commas mark small pauses and help show the structure and emphasis:

…· εγώ, αντίθετα, θέλω σιωπή.

Here εγώ is separated to give extra focus to I, and αντίθετα is treated as a parenthetical adverb, similar to English “I, on the other hand, want silence.”

You could write:

…· εγώ αντίθετα θέλω σιωπή.

This is also acceptable; it just feels slightly less “carefully written.” The commas mainly affect rhythm and emphasis, not the basic meaning.

Why is it θέλω σιωπή without an article? Could I say θέλω τη σιωπή?

Θέλω σιωπή literally means I want silence, in the sense of I want (there to be) silence / I want quiet.

With abstract and uncountable nouns, Greek often drops the article when you mean the concept in a general, indefinite way:

θέλω ησυχία = I want quiet
θέλω καφέ = I want (some) coffee

You can say θέλω τη σιωπή, but that would sound like you are talking about some specific silence (for example, τη σιωπή of a particular moment, or almost personifying silence). In everyday speech, θέλω σιωπή is the natural way to say I want silence / I want it to be quiet.

Is σιωπή related to a verb meaning to be silent? How would I say be quiet! or keep silent?

Yes, σιωπή (silence) is related to the verb σιωπώ (to be silent, to keep silent).

Some useful related forms:

σιωπώ = I am silent / I keep silent
η σιωπή = silence
σιωπηλός (adj.) = silent (person), quiet

For be quiet! / be silent!, more common everyday expressions are:

Ησυχία! = Quiet!
Σκάσε! (very informal / rude) = Shut up!

Σιωπή! is also used, but it sounds a bit formal or commanding, e.g. by a teacher, director, etc.

Could I change the word order and say: Εγώ θέλω σιωπή, η αδερφή μου δουλεύει καλύτερα με μουσική?

Yes, that order is grammatically correct and understandable:

Εγώ θέλω σιωπή, η αδερφή μου δουλεύει καλύτερα με μουσική.

However, the original version:

Η αδερφή μου δουλεύει καλύτερα με μουσική· εγώ, αντίθετα, θέλω σιωπή.

sounds more natural because it presents one person’s preference first and then directly introduces the contrast with εγώ, αντίθετα. Your alternative loses the explicit contrast word αντίθετα and changes the rhythm, so it feels a bit flatter. If you keep αντίθετα, it’s better positioned near εγώ or at the start of the second clause.