Πριν βγουν έξω, άλλαξαν την πάνα και πήραν μαζί τους ένα καθαρό μπιμπερό.

After πριν when Greek means before someone does/did something, it often uses the subjunctive form, sometimes with να and sometimes without it.

So:

• Πριν βγουν έξω = before they go/went out
• Πριν να βγουν έξω = also possible, with the same meaning

Here βγουν is the aorist subjunctive of βγαίνω. It does not mean present tense. It refers to the action as a whole: go out.

Compare:

• βγαίνουν = they are going out / they go out
• βγήκαν = they went out
• βγουν = (that) they go out / before they go out / when they go out, depending on context

So πριν βγουν έξω is the normal structure here.

Yes, πριν να βγουν έξω is also correct.

In modern Greek, after πριν, both patterns are common:

• πριν βγουν έξω
• πριν να βγουν έξω

The version without να is very common, especially in everyday language. So the sentence is perfectly natural as written.

Yes, βγαίνω already means go out / come out, so έξω is partly reinforcing that idea.

• βγαίνω = I go out
• βγαίνω έξω = I go outside / I go out

In everyday Greek, using both together is extremely common and sounds natural. It is a bit like how some languages often say something like go out outside even if one word already contains the idea.

So βγουν έξω is not strange or redundant in normal speech.

Both are aorist forms, which are commonly used for completed actions in the past.

• άλλαξαν = they changed
• πήραν = they took

In this sentence, the speaker is describing a sequence of completed actions:

1. Before going out,
2. they changed the diaper,
3. and took a clean bottle with them.

The aorist is the natural tense here because these are single completed actions, not ongoing background actions.

Greek usually does not need a separate subject pronoun if the verb ending already shows the subject.

Here:

• βγουν = they go out
• άλλαξαν = they changed
• πήραν = they took

So the subject they is built into the verb endings. Greek often leaves pronouns like αυτοί out unless it wants emphasis or contrast.

Greek uses the definite article very often, more often than English in some contexts.

Here:

• την πάνα = the diaper

This is the normal way to say it. Greek generally prefers the article with concrete nouns in ordinary situations, especially when the thing is specific in context.

So even if English and Greek both use the here, it is useful to remember that Greek article usage is generally broader and more regular.

Grammar here:

• πάνα is feminine singular
• την is the feminine singular accusative article, because it is the direct object of άλλαξαν

μαζί τους means with them.

It is made of:

• μαζί = together / with
• τους = them

In Greek, μαζί often combines with a pronoun to express with someone:

• μαζί μου = with me
• μαζί σου = with you
• μαζί του/της = with him/her
• μαζί μας = with us
• μαζί σας = with you (plural/formal)
• μαζί τους = with them

So πήραν μαζί τους ένα καθαρό μπιμπερό literally means they took with them a clean baby bottle.

This is a very natural Greek way to say it.

Yes, absolutely.

Both are natural:

• πήραν μαζί τους ένα καθαρό μπιμπερό
• πήραν ένα καθαρό μπιμπερό μαζί τους

The difference is mainly one of emphasis and flow.

• πήραν μαζί τους... puts with them earlier, so it highlights the idea of taking it along.
• πήραν ένα καθαρό μπιμπερό μαζί τους puts the object first and then adds with them.

Greek word order is more flexible than English because the case system and verb endings carry a lot of grammatical information.

καθαρό agrees with μπιμπερό in gender, number, and case.

Here:

• ένα = a / one, neuter singular accusative/nominative
• καθαρό = clean, neuter singular accusative/nominative
• μπιμπερό = baby bottle, neuter singular

So καθαρό is the neuter singular form of the adjective καθαρός.

Basic forms are:

• καθαρός = masculine
• καθαρή = feminine
• καθαρό = neuter

Because μπιμπερό is neuter, the adjective must also be neuter: καθαρό μπιμπερό.

Yes, it is a normal everyday word in modern Greek, but it is a loanword.

μπιμπερό means baby bottle / feeding bottle. It is very common in spoken Greek.

A useful thing to notice is that μπιμπερό is generally treated as neuter and is often indeclinable, meaning its form usually does not change across cases:

• το μπιμπερό
• ένα μπιμπερό
• του μπιμπερό

So in this sentence, ένα καθαρό μπιμπερό is a very ordinary phrase.

Greek often uses παίρνω (take) where English might also think of bring, depending on perspective.

• παίρνω μαζί μου = take with me
• φέρνω = bring

In this sentence, the viewpoint is from the people leaving the house. They are taking the bottle along with them, so πήραν μαζί τους is exactly right.

English also commonly says they took a clean bottle with them, so the match is quite direct here.

It can correspond to either in English, depending on the time frame of the main verb.

Because the main verbs here are past tense:

• άλλαξαν
• πήραν

the whole sentence is understood in the past:

• Before they went out, they changed the diaper and took a clean bottle with them.

But the Greek structure itself is not a simple past tense form in the πριν clause. It is a subjunctive construction whose time is understood from context.

That is very common in Greek subordinate clauses.

Literally, it is just they changed the diaper.

But in real-life context, Greek often leaves out information that is obvious. So here it naturally means something like:

• they changed the baby’s diaper
• they changed the diaper

Both are good translations depending on how explicit you want to be in English.

Greek does not need to mention the baby’s if the context already makes it obvious.