Το κορίτσι βάζει ένα παγάκι στον χυμό της, γιατί δεν είναι κρύος.

In Greek, grammatical gender and natural gender are not always the same.

Κορίτσι means girl, but it is a neuter noun, so it takes the neuter article το:

• το κορίτσι = the girl

This is something learners just have to memorize with the noun. Even though the person is female, the noun itself is grammatically neuter.

Βάζει is the 3rd person singular present form of βάζω, which means to put.

So:

• βάζω = I put / I am putting
• βάζει = he/she/it puts / is putting

Here it matches το κορίτσι, so it means the girl puts.

Because παγάκι is a neuter noun.

The indefinite article a/an changes according to gender:

• ένας for masculine
• μία / μια for feminine
• ένα for neuter

So:

• ένα παγάκι = an ice cube

You would only use έναν with a masculine noun in the accusative, not with a neuter noun.

Usually παγάκι means ice cube.

It comes from πάγος = ice, and -άκι is a very common diminutive ending in Greek. Very often, though, παγάκι is simply the normal everyday word for an ice cube, not necessarily a cute or tiny one.

So in this sentence:

• ένα παγάκι = an ice cube

Στον is a contraction of:

• σε = in, into, to, at
• τον = the (masculine accusative singular)

So:

• σε τον → στον

Here:

• στον χυμό = into the juice / in the juice

This contraction is very common in modern Greek:

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

The dictionary form is ο χυμός = the juice.

In this sentence, it becomes τον χυμό because it comes after σε / στον, which normally takes the accusative in modern Greek.

So:

• nominative: ο χυμός
• accusative: τον χυμό

That is why you see στον χυμό and not στον χυμός.

Here της means her.

Greek often uses a weak possessive form that looks like the genitive pronoun:

• μου = my
• σου = your
• του / της = his / her
• μας = our
• σας = your
• τους = their

So:

• ο χυμός της = her juice

In Greek, this possessive word usually comes after the noun, unlike English:

• English: her juice
• Greek: ο χυμός της

Greek uses the definite article much more often than English.

When a noun is possessed, Greek very commonly keeps the article:

• ο φίλος μου = my friend
• το σπίτι της = her house
• στον χυμό της = in her juice

So even though English says her juice, Greek naturally says something closer to the juice of hers.

Yes, γιατί can mean both why and because.

You understand which one it is from the structure of the sentence:

• in a question: Γιατί...; = Why...?
• in a statement: ..., γιατί ... = ..., because ...

Here it introduces a reason:

• γιατί δεν είναι κρύος = because it is not cold

This is very normal in Greek.

Because κρύος agrees with χυμός, which is a masculine noun.

• ο χυμός = the juice
• κρύος = cold (masculine form)

In Greek, adjectives agree with the noun they describe in gender, number, and case.

So:

• masculine: κρύος
• feminine: κρύα
• neuter: κρύο

Even though English says it isn’t cold, Greek is really saying the juice is not cold, so the adjective has to match χυμός.

Greek often leaves out subject pronouns when they are clear from the verb or the context.

So instead of saying:

• it is not cold

Greek can simply say:

• δεν είναι κρύος = is not cold

The listener understands that the missing subject is the juice.

This is very common in Greek. Subject pronouns are only added when needed for emphasis or clarity.

Greek word order is more flexible than English, but this version is very natural.

The sentence:

• Το κορίτσι βάζει ένα παγάκι στον χυμό της, γιατί δεν είναι κρύος.

is a normal, straightforward order:

1. subject
2. verb
3. object
4. prepositional phrase
5. reason clause

Some parts could move for emphasis, but this version is probably the most neutral and learner-friendly one.