Learn Hardcore Greek: Η φίλη μου σπουδάζει στο τμήμα ψυχολογίας και μοιράζεται μαζί μου τις σημειώσεις της. - My friend studies in the psychology department and shares her notes with me.

φίλη μου (without the article) is usually:
- used after the verb είμαι: Είναι φίλη μου. = She is a friend of mine.
- or as a form of address: Φίλη μου, έλα εδώ. = My friend, come here.
η φίλη alone just means the (female) friend with no idea of my.

So in your sentence, Η φίλη μου is exactly my friend, specific and definite, and you normally keep both the article and μου.

Why is it φίλη and not φίλος? What is the difference?

Greek makes a gender distinction:

ο φίλος = (male) friend
η φίλη = (female) friend

Since the person in the sentence is female, the feminine form η φίλη is used. The possessive μου (my) doesn’t change with gender; only the noun and its article do:

ο φίλος μου = my (male) friend
η φίλη μου = my (female) friend

Why is there no word for she in the sentence? How do we know it means she studies?

Greek usually drops subject pronouns when the subject is clear from the verb ending.

σπουδάζω = I study
σπουδάζεις = you (sg) study
σπουδάζει = he/she/it studies

Here we have σπουδάζει, which can mean he/she studies. The subject is made clear by η φίλη μου, so Greek does not need an extra αυτή (she).

If you said Αυτή η φίλη μου σπουδάζει…, it would sound emphatic: This friend of mine studies…

Does σπουδάζει mean she studies or she is studying? How does the Greek present tense work here?

Greek present tense usually covers both English simple present and present continuous.

Η φίλη μου σπουδάζει στο τμήμα ψυχολογίας.
= My friend studies in the psychology department.
or
= My friend is studying in the psychology department.

Context decides which English translation sounds better. You don’t need a separate form like is studying in Greek; σπουδάζει covers both.

What exactly does στο τμήμα ψυχολογίας mean? Why not just σπουδάζει ψυχολογία?

Both exist, but they’re slightly different:

σπουδάζει ψυχολογία = she studies psychology (the subject)
σπουδάζει στο τμήμα ψυχολογίας = she studies in the psychology department (the official academic unit)

τμήμα means department/section. So:

το τμήμα ψυχολογίας = the psychology department
στο τμήμα ψυχολογίας = σε + το τμήμα ψυχολογίας → στο τμήμα ψυχολογίας = in the psychology department

What is στο exactly? Why is it not just σε το?

στο is the contraction of the preposition and article:

σε + το → στο
meaning: in the / at the / to the (for neuter singular nouns)

Similarly:

σε + τον → στον
σε + την → στη(ν)
σε + τους → στους
σε + τις → στις

So στο τμήμα literally is in-the department.

Why is it τμήμα ψυχολογίας and not something like ψυχολογικό τμήμα?

Greek can form this kind of phrase in two main ways:

Noun + genitive noun:
- το τμήμα ψυχολογίας = the department of psychology
- Here ψυχολογίας is genitive singular of η ψυχολογία (psychology).
Adjective + noun:
- το ψυχολογικό τμήμα = the psychological department / the psychology department (less usual as an official name).

For actual university departments, the Noun + genitive pattern (τμήμα ψυχολογίας, τμήμα μαθηματικών, τμήμα ιστορίας) is the standard way to say Department of X.

What is going on with the verb μοιράζεται? Why does it end in -εται and not just -ει like σπουδάζει?

μοιράζεται is the middle/reflexive form of the verb μοιράζομαι = to share.

Active: μοιράζω = I divide, distribute (something to others)
Middle: μοιράζομαι = I share (something with someone)

Conjugation (present, singular):

μοιράζομαι = I share
μοιράζεσαι = you share
μοιράζεται = he/she/it shares

The -εται ending shows this middle/reflexive form. So μοιράζεται means she shares (for herself, with someone), and that’s the natural form for sharing notes with someone.

Does μοιράζεται already mean shares with me? Why do we still need μαζί μου?

μοιράζεται by itself just means she shares (something). It doesn’t specify with whom.

μοιράζεται τις σημειώσεις της = She shares her notes (with someone, unsaid).
μοιράζεται μαζί μου τις σημειώσεις της = She shares her notes with me.

μαζί literally means together; μαζί μου ≈ together with me → with me. So μαζί μου is needed to specify the person she shares the notes with.

What exactly does μαζί μου mean, and why is μου used here instead of a different form?

μαζί = together
μαζί μου = together with me → with me

Greek uses genitive pronouns after many prepositions and with μαζί:

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

The form μου here is the genitive weak pronoun, same shape as the possessive μου in η φίλη μου, but the function is different:

η φίλη μου = my friend (possessive)
μαζί μου = with me (object of together)

How do τις σημειώσεις and της work grammatically at the end of the sentence?

Let’s break it down:

η σημείωση = the note (singular, nominative)
οι σημειώσεις = the notes (plural, nominative)
τις σημειώσεις = the notes (plural, accusative) → direct object

So in the sentence:

μοιράζεται μαζί μου τις σημειώσεις → she shares the notes with me.

Then της is a genitive weak pronoun = her:

τις σημειώσεις της = her notes

Grammar roles:

τις σημειώσεις: direct object (what she shares)
της: shows whose notes they are (possessor).

Why is the possessive της at the end (τις σημειώσεις της)? Could it go before the noun like in English?

In Greek, possessive clitic pronouns (μου, σου, του, της, μας, σας, τους) normally come after the noun:

το βιβλίο μου = my book
οι φίλοι σου = your friends
τις σημειώσεις της = her notes

To put a possessive before the noun, you need the emphatic forms δικός / δική / δικό:

οι δικές της σημειώσεις = her own notes (more emphasis, more contrastive)

So:

τις σημειώσεις της = her notes (neutral)
τις δικές της σημειώσεις = her notes (as opposed to someone else’s, emphatic)

Is της really necessary? Doesn’t η φίλη μου already make it clear that the notes are hers?

Not necessarily. Without της, τις σημειώσεις just means the notes:

They could be:
- general course notes,
- the lecturer’s notes,
- some shared notes,
- or previously mentioned notes.

By adding της, you make it explicit:

τις σημειώσεις της = her notes, the ones that belong to her.

In real speech, if it were absolutely obvious whose notes they are, a speaker might omit της, but the natural, clear way is to include it, as in your sentence.

Can the word order of μαζί μου τις σημειώσεις της change? For example, is μοιράζεται τις σημειώσεις της μαζί μου also correct?

Yes, Greek word order is relatively flexible, especially with adverbials like μαζί μου.

All of these are grammatically correct, with only slight changes in emphasis:

μοιράζεται μαζί μου τις σημειώσεις της
μοιράζεται τις σημειώσεις της μαζί μου

Both mean she shares her notes with me.
Placing μαζί μου earlier or later can lightly affect rhythm or focus, but it doesn’t change the basic meaning here.