Η αδερφή μου κάθεται πάνω σε έναν βράχο και κοιτάει τη θάλασσα.

Η is the feminine singular definite article, meaning the.

So:

• Η αδερφή = the sister

It agrees with αδερφή, which is a feminine singular noun.

A useful thing to remember is that Greek articles change for gender, number, and case, unlike English the, which never changes.

In Greek, possessive words like μου (my) usually come after the noun.

So:

• η αδερφή μου = my sister
• literally: the sister my

This is the normal Greek pattern for possessives:

• το βιβλίο μου = my book
• η μητέρα μου = my mother
• ο φίλος μου = my friend

Greek often keeps the article even when English would not, so η αδερφή μου is the natural way to say my sister.

Both αδερφή and αδελφή mean sister.

• αδερφή is very common in everyday modern speech
• αδελφή is also correct, and may sound a bit more formal or conservative in some contexts

For a learner, αδερφή is perfectly natural and very common in spoken Greek.

Κάθομαι is the dictionary form, meaning I sit / I am sitting.

In the sentence, the subject is η αδερφή μου = my sister, which is third person singular (she), so the verb changes:

• κάθομαι = I sit / am sitting
• κάθεσαι = you sit / are sitting
• κάθεται = he/she/it sits / is sitting

So:

• Η αδερφή μου κάθεται = My sister is sitting

Greek verbs change form according to the subject, much more than English verbs do.

It can mean both, depending on context.

Greek present tense often covers both:

• a general present: sits
• an action happening now: is sitting

In this sentence, English would most naturally translate it as is sitting, because it describes a scene:

• My sister is sitting on a rock and looking at the sea

But sits is not grammatically wrong as a general meaning of the verb.

πάνω σε means on or on top of.

It is a common Greek expression made up of:

• πάνω = above / on top
• σε = on / in / at / to

Together, πάνω σε means something like on top of / on.

So:

• πάνω σε έναν βράχο = on a rock

Greek often uses multi-word expressions where English uses a single preposition.

έναν is the masculine singular accusative form of the indefinite article, meaning a / an.

Here:

• βράχος = rock
• έναν βράχο = a rock

The preposition σε normally takes the accusative case, so both the article and the noun appear in accusative form:

• nominative: ένας βράχος
• accusative: έναν βράχο

That is why you see έναν βράχο, not ένας βράχος.

Because it is in the accusative case.

The basic form of the noun is:

• ο βράχος = the rock

But after σε, Greek uses the accusative:

• σε έναν βράχο = on a rock

For many masculine nouns ending in -ος, the accusative singular ends in -ο:

• ο φίλος → τον φίλο
• ο δρόμος → τον δρόμο
• ο βράχος → τον βράχο

So βράχο is the case form required by the sentence.

Because Greek usually does not need subject pronouns when the verb already shows the person.

The subject here is already given as:

• Η αδερφή μου

After that, Greek naturally continues with the verbs without repeating she.

Also, the verb endings themselves help show the person:

• κάθεται
• κοιτάει

So Greek often sounds more natural without extra subject pronouns unless there is emphasis, contrast, or possible confusion.

Κοιτάει means looks or is looking.

Yes, it is closely related to κοιτάζει. In modern Greek, both forms are used:

• κοιτάει
• κοιτάζει

They both mean the same thing here. In everyday speech, κοιτάει is very common.

So:

• κοιτάει τη θάλασσα = is looking at the sea

For a learner, it is useful to recognize both forms as normal modern Greek.

Because θάλασσα is the object of the verb κοιτάει.

The dictionary/basic form is:

• η θάλασσα = the sea

But as a direct object, it goes into the accusative:

• τη θάλασσα = the sea

For many feminine nouns, the noun itself may stay the same, but the article changes:

• nominative: η θάλασσα
• accusative: τη θάλασσα

So the article shows the case change clearly.

Both τη and την can be correct.

Την is the full accusative feminine singular article, but in modern Greek the final -ν is often dropped before certain sounds.

So:

• την θάλασσα
• τη θάλασσα

Both are used, and τη θάλασσα is completely normal.

In general, whether the final -ν stays or drops depends on pronunciation rules and style. Learners will see both spellings, so it is good to get used to them.

Because Greek uses the verb κοιτάω / κοιτάζω directly with an object.

So Greek says:

• κοιτάω τη θάλασσα
• literally: I look the sea

English needs the preposition at, but Greek does not here.

This is a very common difference between languages: one language uses a preposition, while another uses a direct object.

Και means and.

It joins the two verbs:

• κάθεται = is sitting
• κοιτάει = is looking

So the structure is:

• Η αδερφή μου κάθεται πάνω σε έναν βράχο και κοιτάει τη θάλασσα.
• My sister is sitting on a rock and looking at the sea.

It connects two actions done by the same subject.

Greek word order is often more flexible than English word order.

This sentence is very natural as it stands, but other versions are possible, especially for emphasis. For example, Greek could move parts around to highlight the place or the object.

Still, the given order is a very normal neutral order:

• subject: Η αδερφή μου
• verb: κάθεται
• place phrase: πάνω σε έναν βράχο
• second verb: και κοιτάει
• object: τη θάλασσα

As a beginner, it is best to learn this version first, because it sounds natural and clear.

Yes, the written accents matter because they show where the stress falls.

In this sentence:

• αδερφή
• κάθεται
• πάνω
• έναν
• βράχο
• κοιτάει
• θάλασσα

Greek stress is important for correct pronunciation, and sometimes it can also help distinguish forms.

For example:

• μου has no written accent because it is an unstressed weak form
• αδερφή is stressed on the last syllable
• βράχο is stressed on the first syllable

Paying attention to stress early is very helpful when learning Greek pronunciation.