Η κόρη της φίλης μου θέλει ροζ σορτς το καλοκαίρι, αλλά ο γιος της προτιμάει μπλε.

They are the definite articles the.

• η κόρη = the daughter
• ο γιος = the son

Greek uses definite articles very often, including with people and family members in normal statements. So where English might sometimes focus on the possessive idea, Greek still naturally says the daughter, the son, etc.

Also, the form of the article changes with gender, number, and case:

• η = feminine singular nominative
• ο = masculine singular nominative

That matches:

• κόρη = feminine
• γιος = masculine

Because this part means of my friend, not my friend as the subject.

Greek often expresses possession with the genitive, where English often uses of or the apostrophe 's.

So:

• η φίλη μου = my friend
• της φίλης μου = of my friend

That is why:

• η κόρη της φίλης μου literally = the daughter of my friend

This is the Greek way to say my friend's daughter.

No. It looks the same, but it has two different jobs.

1. In της φίλης μου, της is the genitive article

   • της φίλης = of the friend

2. In ο γιος της, της is the weak possessive pronoun meaning her

   • ο γιος της = her son

So the two της forms are identical in spelling, but not identical in function.

A useful shortcut:

• της + noun often means of the ...
• noun + της often means her

Because Greek weak possessive pronouns normally come after the noun they belong to.

So:

• η φίλη μου = my friend
• ο αδερφός μου = my brother
• το σπίτι μου = my house

In this sentence, μου belongs to φίλης, not to κόρη. That is important.

• της φίλης μου = of my friend
• the whole phrase η κόρη της φίλης μου = my friend's daughter

If μου came with κόρη, the meaning would change:

• η κόρη μου = my daughter

Because Greek does not have a separate indefinite article in the plural.

English can say:

• pink shorts
• some pink shorts

Greek can simply say:

• ροζ σορτς

That works naturally for an indefinite plural idea.

So after θέλει, Greek does not need an extra word there. The phrase just means something like wants pink shorts.

Because these color words are usually indeclinable in Modern Greek.

That means they do not change to match gender, number, or case.

For example:

• ροζ φόρεμα
• ροζ μπλούζα
• ροζ σορτς

and

• μπλε πουκάμισο
• μπλε φούστα
• μπλε παπούτσια

The form stays the same.

That is different from adjectives like μεγάλος / μεγάλη / μεγάλο, which do change.

σορτς is a borrowed word from English, and it is usually treated as an indeclinable noun in Greek.

Its form often stays the same:

• το σορτς
• τα σορτς

In actual use, the meaning tells you whether it is singular or plural. In this sentence, it is understood as shorts.

Because it is a loanword and indeclinable, learners often notice that it does not behave like a typical Greek noun.

It means in the summer or during the summer.

This is a very common Greek time expression: article + season/time noun.

So:

• το καλοκαίρι = in the summer
• τον χειμώνα = in the winter
• την άνοιξη = in the spring

Here καλοκαίρι is neuter, so the article is το.

This whole phrase functions adverbially, telling you when the daughter wants the shorts.

Because Greek, like English, can leave out a noun if it is already clear from context.

So:

• ο γιος της προτιμάει μπλε

means:

• her son prefers blue ones
• more fully: her son prefers blue shorts

The noun σορτς is omitted because it is easily understood from the earlier part of the sentence.

English does this too:

• She wants pink shorts, but he prefers blue.

Yes. Both are 3rd person singular present tense forms.

• θέλει = he/she wants
• προτιμάει = he/she prefers

They match the singular subjects:

• η κόρη ... θέλει
• ο γιος ... προτιμάει

So the agreement is:

• singular feminine noun → 3rd person singular verb
• singular masculine noun → 3rd person singular verb

The verb form does not change for gender, only for person and number.

Also, with προτιμάω, you may also see the shorter form προτιμά. Both are common:

• προτιμάει
• προτιμά

Yes, that is the natural reading here.

The structure is:

• η κόρη της φίλης μου = my friend's daughter
• αλλά ο γιος της = but her son

Here της most naturally refers back to της φίλης μου, so her son means my friend's son.

Greek often uses these short possessive pronouns very economically, and context tells you who the possessor is.