Ο κύριος που μιλάει με τη γιατρό είναι κουρασμένος.

In Greek, the definite article is used much more often than in English. Ο κύριος means the man / the gentleman / the sir depending on context.

If you said just κύριος, it would usually not sound complete here. Greek normally wants the article with a noun when you are talking about a specific person:

• ο κύριος = the man
• η γιατρός = the doctor (female)

So Ο κύριος που μιλάει... is the natural way to say The man who is talking...

Here που means who or that in a relative clause.

So:

• ο κύριος = the man
• που μιλάει με τη γιατρό = who is talking with the doctor

Together:

• Ο κύριος που μιλάει με τη γιατρό = The man who is talking with the doctor

In modern Greek, που is a very common and simple way to introduce relative clauses.

Yes. In many sentences, που can be translated as either who, which, or that, depending on the noun before it.

For example:

• ο άνθρωπος που ήρθε = the person who came
• το βιβλίο που αγόρασα = the book that I bought

So in your sentence, English prefers who, because it refers to a person, but the Greek word is still just που.

Yes. Both μιλάει and μιλά are correct in modern Greek.

They are two common forms of the same verb:

• μιλάει = he/she is speaking / talks
• μιλά = same meaning

So these are both natural:

• Ο κύριος που μιλάει με τη γιατρό...
• Ο κύριος που μιλά με τη γιατρό...

The version with -άει is often very common in everyday speech and writing.

Greek usually does not need subject pronouns, because the verb ending already tells you the person and number.

So:

• μιλάω = I speak
• μιλάς = you speak
• μιλάει = he/she speaks

Because of that, Greek often leaves out I, you, he, she, unless there is special emphasis or contrast.

Here, που μιλάει already clearly means who is talking, so αυτός is unnecessary.

Yes, με usually means with.

So μιλάει με τη γιατρό means:

• he is talking with the doctor
• often naturally translated as he is talking to the doctor

Greek uses με with μιλάω to express speaking with someone.

So although English often says talk to someone, Greek commonly says μιλάω με κάποιον.

Because after the preposition με, the noun goes in the accusative case.

The dictionary form is:

• η γιατρός = the doctor (female) — nominative

But after με, you need accusative:

• τη(ν) γιατρό = the doctor (female) — accusative

So:

• η γιατρός μιλάει = the doctor is speaking
• μιλάει με τη γιατρό = he is speaking with the doctor

This is one of the basic case changes Greek learners need to get used to.

Both are possible.

The full form is την, but in everyday Greek the final -ν is often dropped before many consonants. So:

• την γιατρό = correct
• τη γιατρό = also correct and very common

You will often see την kept before vowels and certain consonants, but everyday usage varies. In this sentence, τη γιατρό sounds completely natural.

This is a very good question, because it can feel unusual to English speakers.

The word γιατρός can be used for both a male and a female doctor. The article shows the gender:

• ο γιατρός = the male doctor
• η γιατρός = the female doctor

In the accusative:

• τον γιατρό = the male doctor
• τη(ν) γιατρό = the female doctor

So the noun form stays basically the same, while the article tells you whether the doctor is male or female.

Κουρασμένος means tired, but it is actually an adjective that changes form depending on gender and number.

Because it describes ο κύριος (the man), it must be masculine singular:

• κουρασμένος = masculine singular
• κουρασμένη = feminine singular
• κουρασμένο = neuter singular

So:

• Ο κύριος είναι κουρασμένος. = The man is tired.
• Η γυναίκα είναι κουρασμένη. = The woman is tired.
• Το παιδί είναι κουρασμένο. = The child is tired.

Because Greek normally uses the verb είμαι (to be) in this kind of sentence, just like English does.

So:

• είναι κουρασμένος = is tired

You may sometimes hear short answers where the verb is omitted in casual speech, but in a full sentence like this, είναι is standard and necessary.

It is present tense.

So που μιλάει με τη γιατρό means:

• who is talking with the doctor
• or sometimes who talks with the doctor, depending on context

In this sentence, English most naturally uses is talking, because it sounds like a person identified by what he is doing right now.

Not completely. Greek word order is more flexible than English word order, because Greek uses articles and case endings to show relationships.

The given sentence is the most neutral and natural order:

• Ο κύριος που μιλάει με τη γιατρό είναι κουρασμένος.

But Greek can move things around for emphasis more easily than English can. Still, for a learner, this word order is the best one to copy.

A useful way to see the structure is:

• Ο κύριος = subject
• που μιλάει με τη γιατρό = relative clause describing the subject
• είναι κουρασμένος = main predicate

Yes, but που is the most common and natural choice here.

A more formal alternative would be something like:

• Ο κύριος ο οποίος μιλάει με τη γιατρό είναι κουρασμένος.

This also means the same thing, but it sounds heavier and more formal. In everyday Greek, που is usually preferred.

It can mean several related things depending on context:

• man
• gentleman
• sir
• Mr.

In this sentence, ο κύριος most naturally means the man.

If it were before a name, it could mean Mr.:

• ο κύριος Παπαδόπουλος = Mr. Papadopoulos

So context decides the best English translation.

A very close word-for-word breakdown is:

• Ο = the
• κύριος = man / gentleman
• που = who / that
• μιλάει = is talking / talks
• με = with
• τη = the
• γιατρό = doctor
• είναι = is
• κουρασμένος = tired

So the structure is very close to English:

• The man who is talking with the doctor is tired.

That makes this a very useful sentence for seeing how Greek relative clauses work.