Στην πρεμιέρα ανοίγει η αυλαία.

Because στην is the usual contracted form of σε + την.

So:

• σε = in / at / to
• την = the (feminine accusative singular)

Together they become στην.

This is very common in Greek:

• σε + τον = στον
• σε + τη(ν) = στη(ν)
• σε + το = στο

So Στην πρεμιέρα means at the premiere.

Because the next word starts with π, and in standard spelling the final -ν is kept before certain sounds, including π.

So:

• στην πρεμιέρα is the expected form

You will sometimes hear variation with final -ν in speech in other contexts, but here στην is the normal choice.

Because it comes after the preposition σε, and σε takes the accusative case in Modern Greek.

So the phrase is:

• στην πρεμιέρα = at the premiere

The noun πρεμιέρα is feminine, and here it appears in the accusative singular with the article built into στην.

Πρεμιέρα is a loanword, but it behaves like a normal Greek noun.

Its gender is feminine:

• η πρεμιέρα = the premiere
• της πρεμιέρας = of the premiere
• την πρεμιέρα = the premiere (object / after σε)

So in this sentence it is just an ordinary feminine noun grammatically.

Ανοίγει is the:

• present tense
• third person singular
• from the verb ανοίγω = to open

So ανοίγει means:

• it opens
• he/she opens, depending on context

In this sentence, it matches η αυλαία, so it means the curtain opens.

Because Greek commonly uses the verb ανοίγω for a curtain.

Literally, η αυλαία ανοίγει is the curtain opens, but in natural English the equivalent is often:

• the curtain rises
• the curtain goes up

So the Greek is normal and idiomatic, even if English chooses a different verb.

Because the article shows the case.

• η αυλαία = nominative → subject
• την αυλαία = accusative → object

So here η αυλαία is clearly the subject: the curtain.

If it were the object, you would expect την αυλαία instead.

Greek word order is more flexible than English because case endings and articles make grammatical roles clearer.

Both of these are possible:

• Η αυλαία ανοίγει
• Ανοίγει η αυλαία

The version with the verb first can sound more natural in narrative or descriptive style, and it can put a little more focus on the action.

So ανοίγει η αυλαία is not strange at all.

Not necessarily. The present tense in Greek can describe:

• something happening now
• something that generally happens
• a vivid, scene-setting statement

So Στην πρεμιέρα ανοίγει η αυλαία can mean something like:

• At the premiere, the curtain goes up
• At the premiere, the curtain rises

It sounds like a general or descriptive statement.

If you wanted to talk about a specific future event more explicitly, Greek could use the future:

• Στην πρεμιέρα θα ανοίξει η αυλαία.

It can be both.

Literally, it refers to an actual curtain opening at the start of a performance.

But η αυλαία ανοίγει can also feel a bit theatrical or figurative, suggesting:

• the show is beginning
• the event is starting
• the action is about to begin

Greek often uses theater-related language this way.

A rough pronunciation is:

stin pre-MYE-ra a-NI-yi i av-LE-a

A few useful notes:

• στην sounds like stin
• πρεμιέρα has the stress on -έ-
• ανοίγει sounds roughly like a-NI-yi
• η is pronounced i
• αυλαία begins with av-, not af-, because αυ before λ is pronounced av

So the full sentence flows roughly as:

stin pre-MYE-ra a-NI-yi i av-LE-a