Learn Hardcore Greek: Πριν να κοιμηθώ, κλείνω την κουρτίνα στο δωμάτιο για να μην μπαίνει φως. - Before I sleep, I close the curtain in the room so that no light comes in.

πριν + subjunctive (πριν κοιμηθώ) is slightly more common and a bit “cleaner” stylistically.
πριν να + subjunctive (πριν να κοιμηθώ) is also used a lot in everyday speech, and many Greeks say it naturally without thinking.

So:

You can drop να: Πριν κοιμηθώ, κλείνω την κουρτίνα…
Using να is not wrong; it’s just a variant. Some teachers prefer to teach πριν without να for simplicity and style.

Why is it κοιμηθώ and not κοιμάμαι?

Both verbs are related to sleeping, but they focus on different things:

κοιμάμαι = I sleep / I am sleeping (the state or process of sleeping)
κοιμηθώ = I (go to) sleep / I fall asleep (the moment of starting to sleep)

Here we say πριν να κοιμηθώ = before I go to sleep, i.e. before the event or moment of falling asleep.

You wouldn’t normally say:

✗ πριν να κοιμάμαι – this sounds wrong in modern Greek

After πριν, when you mean “before I do X (once)”, you usually use the aorist subjunctive form, which here is κοιμηθώ.

Why is κλείνω in the present tense? In English I might say “Before I sleep, I close / I’m closing the curtain.”

Greek present κλείνω can express:

a habitual action: something you normally do
or a present-time action: what you’re doing now

So:

Πριν να κοιμηθώ, κλείνω την κουρτίνα…
= Before I sleep, I (always) close the curtain…
or
= Before I (am going to) sleep, I (now) close the curtain…

Context will decide whether it feels more like a habit or a specific instance. The present simple κλείνω covers both uses that English would split into I close and I am closing.

Why do we say την κουρτίνα with the article? Could we just say κλείνω κουρτίνα?

In Greek, you normally use the definite article with concrete, countable objects, even when English might drop it.

κλείνω την κουρτίνα
literally: I close *the curtain*
This is what you naturally say when referring to the curtain in your room / house.

Without the article:

κλείνω κουρτίνα sounds incomplete or unnatural in standard Greek. It might work only in very telegraphic style (e.g. headlines, notes).

So in everyday speech, say την κουρτίνα.

Why is it singular κουρτίνα and not plural κουρτίνες?

That’s mostly context and choice:

την κουρτίνα = the (single) curtain
τις κουρτίνες = the curtains (plural)

If your room has only one curtain, singular is obvious. Even if there are two curtains on one window, many speakers still say singular, thinking of the whole thing as one “curtain setup”.

You can say:

Πριν να κοιμηθώ, κλείνω τις κουρτίνες…

Both are grammatically correct; the original just imagines one curtain.

What exactly does στο δωμάτιο mean? Why στο and not something else?

στο is a contraction:

στο = σε + το
σε = in / at / to
το = the (neuter singular article)

So:

στο δωμάτιο = in the room / in my room

Grammatically:

δωμάτιο is neuter, singular, accusative, because σε
- a noun usually takes the accusative case.

You could also say:

κλείνω την κουρτίνα του δωματίου = I close the room’s curtain
(more explicit but less everyday than στο δωμάτιο in this context).

Why do we need για να? Could we just say να μην μπαίνει φως?

για να introduces a purpose: “in order to / so that”.
να by itself often just links to a verb (subjunctive), without clearly marking purpose.

Compare:

κλείνω την κουρτίνα για να μην μπαίνει φως
= I close the curtain so that no light enters.

If you drop για and say:

κλείνω την κουρτίνα να μην μπαίνει φως

This can still be understood, but sounds more colloquial and a little less clear. The “reason” or “purpose” is much more explicit with για να.

For standard, clear Greek, keep για να for purpose clauses.

Why is the negative μην and not δεν in για να μην μπαίνει φως?

Greek has two main negatives:

δεν: used with normal finite verbs in the indicative
e.g. δεν κλείνω, δεν μπαίνει, δεν κοιμάμαι
μη(ν): used with subjunctive (να-clauses), infinitive-like structures, and imperatives
e.g. να μην μπαίνει, να μην φύγω, μη μιλάς

In για να μην μπαίνει φως:

The verb μπαίνει is inside a να-clause (να μπαίνει), which is subjunctive-like.
Therefore, the correct negative is μην, not δεν.

So:

✗ για να δεν μπαίνει φως – incorrect
✓ για να μην μπαίνει φως – correct

Why is the verb μπαίνει used with φως? Can’t we just say “so that no light comes” or “so that it’s not bright”?

Greek uses μπαίνω (to enter, to go in) very commonly in this type of expression:

μπαίνει φως = (literally) light enters / light comes in

It sounds very natural to talk about light (or air, cold, noise) as something that goes in:

μπαίνει φως – light comes in
μπαίνει αέρας – air comes in
μπαίνει κρύο – cold comes in

So:

κλείνω την κουρτίνα … για να μην μπαίνει φως
= I close the curtain so that light doesn’t get in.

You could say other things like:

για να μην είναι φωτεινό το δωμάτιο (so that the room is not bright)

but να μην μπαίνει φως is the most straightforward and idiomatic here.

In για να μην μπαίνει φως, the word order is “not enters light” in English terms. Is it normal in Greek to put the verb before the subject like that?

Yes, very normal. Greek word order is quite flexible.

να μην μπαίνει φως
= literally: so that not enters light

But Greek speakers don’t experience this as strange:

Verb + subject order (μπαίνει φως) is very common, especially with new or less important information at the end.

You could also say:

για να μην μπαίνει το φως
για να μην μπαίνει το φως μέσα

All of these are acceptable; the original simply prefers verb-first.

Why is there a comma after Πριν να κοιμηθώ? Is it required?

Yes, you normally use a comma when the dependent clause (the “before…” part) comes first:

Πριν να κοιμηθώ, κλείνω την κουρτίνα…

If you reverse the order, you usually drop the comma:

Κλείνω την κουρτίνα στο δωμάτιο πριν να κοιμηθώ.

So the pattern is similar to English:

Before I sleep, I close the curtain… (comma if “before…” comes first)
I close the curtain before I sleep. (no comma)

Why don’t we say εγώ? Why is it just κλείνω and κοιμηθώ without a subject pronoun?

Greek is a pro-drop language: the subject pronoun (I, you, he, etc.) is often omitted because the verb ending already shows the person.

κλείνω clearly means I close (1st person singular)
κοιμηθώ (in πριν να κοιμηθώ) is also 1st person singular

You only add εγώ when you want to emphasize the subject:

Εγώ κλείνω την κουρτίνα, όχι ο αδερφός μου.
I’m the one who closes the curtain, not my brother.

In a neutral sentence like yours, leaving out εγώ is the natural choice.

Is να κοιμηθώ like saying “to sleep” in English, an infinitive?

Modern Greek doesn’t have a separate infinitive form like English “to sleep”. Instead, it uses να + verb (subjunctive) to fill many of the same roles.

So:

να κοιμηθώ often corresponds to English to sleep / to go to sleep / that I sleep

For example:

Θέλω να κοιμηθώ. = I want to sleep.
Πρέπει να κοιμηθώ. = I have to sleep.
Πριν να κοιμηθώ… = Before I go to sleep…

So yes, you can think of να κοιμηθώ as the Greek way to express something very close to an infinitive like “(for me) to sleep” in many contexts.

Could we replace για να μην μπαίνει φως with ώστε να μην μπαίνει φως? What’s the difference?

Yes, you can say:

…κλείνω την κουρτίνα στο δωμάτιο ώστε να μην μπαίνει φως.

Both:

για να
ώστε να

introduce a purpose / result clause.

Difference in feel:

για να is the most common, neutral, everyday way to say in order to / so that.
ώστε να is a bit more formal or emphatic, and can lean slightly more toward result (“so that / with the result that”).

In your everyday sentence, για να μην μπαίνει φως is the most natural, but ώστε να μην μπαίνει φως is also grammatically correct and clear.