Ο υπεύθυνος τμήματος μιλάει με τον κηδεμόνα.

Ο is the masculine singular nominative definite article, equivalent to the.

Here it goes with υπεύθυνος, so Ο υπεύθυνος means the person in charge / the responsible one.

Greek articles change for:

• gender
• number
• case

So ο tells you that υπεύθυνος is:

• masculine
• singular
• the subject of the sentence

It is originally an adjective meaning responsible, but here it is being used like a noun.

So ο υπεύθυνος literally means the responsible one, but in normal English we would usually say:

• the person in charge
• the supervisor
• the head

Greek does this a lot: an adjective with an article can function as a noun.

Because τμήματος is in the genitive case, not the nominative.

The base form is:

• το τμήμα = the department / section

But after υπεύθυνος, Greek often uses a genitive to show what someone is responsible for or what area they belong to:

• υπεύθυνος τμήματος = head/person in charge of a department

So τμήματος means of the department.

Greek often leaves out the article in this kind of expression, especially in job titles or role descriptions.

So:

• ο υπεύθυνος τμήματος = the department head / the person in charge of a department

If you added the article, του τμήματος, it would usually sound more specific:

• ο υπεύθυνος του τμήματος = the person in charge of the department

Both can be possible, but they are not used in exactly the same way:

• υπεύθυνος τμήματος often feels more like a title or role
• υπεύθυνος του τμήματος points to a specific department more explicitly

Because the preposition με takes the accusative case in Modern Greek.

The dictionary form is:

• ο κηδεμόνας = the guardian

After με, it changes to:

• τον κηδεμόνα

So:

• με τον κηδεμόνα = with the guardian

This is very common:

• με τον μαθητή
• με τη μητέρα
• με τους γονείς

Because Greek nouns change form depending on case.

The nominative form is:

• ο κηδεμόνας

The accusative singular is:

• τον κηδεμόνα

This is a normal masculine noun pattern in Greek. Many masculine nouns ending in -ας lose the final -ς in the accusative singular.

For example:

• ο μαθητής → τον μαθητή
• ο πατέρας → τον πατέρα
• ο κηδεμόνας → τον κηδεμόνα

μιλάει is the 3rd person singular present tense of μιλάω / μιλώ, meaning to speak / to talk.

Since the subject is singular:

• Ο υπεύθυνος τμήματος = one person

the verb must also be singular:

• μιλάει = he/she is speaking, talks, or is talking

Greek verbs change depending on the subject, so the verb ending tells you who is doing the action.

Yes, in Modern Greek μιλάει and μιλά are both used for he/she speaks.

So these are both natural:

• μιλάει με τον κηδεμόνα
• μιλά με τον κηδεμόνα

In everyday language, both are common. You should recognize both as the same tense and person.

Because Greek does not form the present progressive the same way English does.

English distinguishes:

• he talks
• he is talking

Greek often uses the simple present for both ideas:

• μιλάει

So depending on context, μιλάει can mean:

• he talks
• he is talking
• he speaks

The surrounding situation tells you which English translation fits best.

Yes. Greek word order is more flexible than English because case endings help show each word’s role.

The neutral order here is:

• Ο υπεύθυνος τμήματος μιλάει με τον κηδεμόνα.

But you could also hear:

• Με τον κηδεμόνα μιλάει ο υπεύθυνος τμήματος.
• Μιλάει με τον κηδεμόνα ο υπεύθυνος τμήματος.

These can shift the emphasis, but the basic meaning stays the same.

English usually needs a more fixed word order because it relies less on case endings.

You know from both the article/case and the verb.

The subject is:

• Ο υπεύθυνος τμήματος

Why?

• ο marks a nominative masculine singular noun phrase
• the verb μιλάει is 3rd person singular

The other person is in a prepositional phrase:

• με τον κηδεμόνα

So the person in charge is the one speaking, and the guardian is the person he is speaking with.

Yes. This sentence is talking about a male person in charge, so it uses the masculine form:

• ο υπεύθυνος

If the person were female, it would be:

• η υπεύθυνη τμήματος

And the sentence would become:

• Η υπεύθυνη τμήματος μιλάει με τον κηδεμόνα.

Greek adjectives and many role words change form to match gender.

A simple pronunciation guide is:

O y-PÉF-thi-nos tmí-ma-tos mi-LÁ-i me ton ki-the-MÓ-na

A few helpful notes:

• υ here sounds like English i in many modern pronunciations
• th in υπεύθυνος is like th in think
• δ in κηδεμόνα is like th in this
• the stress matters:
  • υπεύθυνος
  • τμήματος
  • μιλάει
  • κηδεμόνα

Yes, it is a very natural kind of expression in Greek, especially in formal, school, business, or administrative contexts.

It often works like a title:

• υπεύθυνος τμήματος = department head / department manager / person in charge of a department

Greek commonly forms titles this way:

• διευθυντής σχολείου = school principal / director of a school
• υπεύθυνος προγράμματος = program coordinator / person in charge of a program
• καθηγητής πανεπιστημίου = university professor

So this pattern is worth learning well.