Δεν μου αρέσει η αγένεια· όταν κάποιος μιλάει με νεύρα, η συζήτηση χαλάει εύκολα.

Because the Greek verb αρέσω / αρέσει works more like is pleasing to.

So:

• μου αρέσει η αγένεια would literally be something like rudeness is pleasing to me
• with δεν, it becomes rudeness is not pleasing to me

That is why Greek uses:

• μου = to me
• αρέσει = is pleasing

This is one of the most important patterns to get used to in Greek:

• Μου αρέσει ο καφές = I like coffee
• Μου αρέσουν τα βιβλία = I like books

The thing liked is treated as the grammatical subject.

Because the subject is η αγένεια (rudeness), which is singular.

Compare:

• Μου αρέσει η αγένεια → singular subject, so αρέσει
• Μου αρέσουν οι καλοί τρόποι → plural subject, so αρέσουν

A useful rule:

• singular thing liked → αρέσει
• plural things liked → αρέσουν

μου is the weak form of the personal pronoun meaning to me.

In older grammar terms, Greek used to have a dative case, but in Modern Greek this function is usually expressed with forms like μου, σου, του, της, μας, σας, τους.

So in this sentence:

• μου αρέσει = it is pleasing to me

You will see this pattern a lot:

• μου λέει = he/she tells me
• μου δίνει = he/she gives me
• μου φαίνεται = it seems to me

Greek often uses the definite article with abstract nouns where English may not.

So:

• η αγένεια = literally the rudeness, but naturally translated as rudeness

This is very common with abstract ideas and general concepts:

• η αγάπη = love
• η ελευθερία = freedom
• η υπομονή = patience

So even though English may omit the, Greek often keeps the article.

η αγένεια is the noun meaning rudeness / impoliteness.

It is related to the adjective:

• αγενής = rude / impolite

So the pattern is:

• αγενής άνθρωπος = a rude person
• η αγένεια = rudeness

This noun is feminine, which is why it takes η.

Here όταν means when in a general, repeated-situation sense.

The sentence is talking about a general truth:

• όταν κάποιος μιλάει με νεύρα, η συζήτηση χαλάει εύκολα
• when someone speaks irritably/angrily, the conversation breaks down easily

Greek often uses the present tense after όταν for general or habitual situations.

So this is not necessarily one specific event. It means something like:

• whenever someone speaks in an angry way...

Here κάποιος means someone or any person.

In this sentence it has a general meaning:

• όταν κάποιος μιλάει με νεύρα = when someone speaks angrily / when a person speaks irritably

It does not point to a specific known person. It is general and indefinite.

You can think of it as:

• someone
• a person
• anyone, depending on context

Yes. μιλάει and μιλά are both acceptable present-tense forms in Modern Greek.

So these are both possible:

• κάποιος μιλάει με νεύρα
• κάποιος μιλά με νεύρα

They mean the same thing.

A lot of everyday speech uses μιλάει, and many learners first meet that form because it is very clear and easy to recognize. But μιλά is also standard.

Literally, με νεύρα means with nerves.

But idiomatically it means:

• angrily
• irritably
• with tension
• in an agitated way

It is a very natural Greek expression. It does not usually mean someone is merely nervous in the English sense. In many contexts it suggests irritation, anger, or being worked up.

Examples:

• Μου μίλησε με νεύρα. = He/She spoke to me angrily / irritably.
• Μην απαντάς με νεύρα. = Don’t answer angrily.

Because η συζήτηση is the subject of χαλάει.

Structure:

• η συζήτηση = the conversation → subject
• χαλάει = gets spoiled / goes bad / breaks down
• εύκολα = easily

So the clause literally works like:

• the conversation breaks down easily

Since it is the subject, Greek uses the nominative:

• η συζήτηση

χαλάω / χαλάει has a broad range of meanings, including:

• to spoil
• to ruin
• to break
• to go bad
• to mess up

In this sentence, η συζήτηση χαλάει εύκολα means something like:

• the conversation easily goes wrong
• the conversation easily breaks down
• the conversation is easily ruined

So it is not necessarily about something physically breaking. It is about the interaction becoming unpleasant or unsuccessful.

Because εύκολα is an adverb meaning easily, and Greek often places adverbs after the verb or near the end of the clause.

So:

• η συζήτηση χαλάει εύκολα

is a very natural word order.

Greek word order is more flexible than English, so you may also see adverbs in other positions for emphasis, but this placement is neutral and common.

That mark is the ano teleia in Greek punctuation.

It is a kind of higher pause, often functioning roughly like:

• a semicolon
• or sometimes a strong colon-like pause

So in:

• Δεν μου αρέσει η αγένεια· όταν κάποιος μιλάει με νεύρα, η συζήτηση χαλάει εύκολα.

it separates two closely connected statements:

1. I don’t like rudeness
2. when someone speaks angrily, the conversation easily breaks down

It is not the Greek question mark. The Greek question mark looks like ;.

Yes. In everyday Greek, μου is often shortened before a vowel:

• μου αρέσει → μ’ αρέσει

So both are correct:

• Δεν μου αρέσει η αγένεια
• Δεν μ’ αρέσει η αγένεια

The full form is a little more explicit in writing or careful speech, while the shortened form is very common in natural spoken Greek and informal writing.