Learn Hardcore Greek: Αυτή η παρουσίαση είναι υπέροχη ευκαιρία να μιλήσω ελληνικά μπροστά σε άλλους. - This presentation is a wonderful opportunity to speak Greek in front of others.

Using only the demonstrative (Αυτή παρουσίαση) is not standard in this context; it sounds wrong or very foreign. The pattern [demonstrative] + [article] + [noun] is the normal one.

Could we also say Η παρουσίαση αυτή instead of Αυτή η παρουσίαση? Is there any difference?

Yes, that’s also correct:

Αυτή η παρουσίαση
Η παρουσίαση αυτή

Both mean “this presentation”.

Differences:

Αυτή η παρουσίαση is the most common, neutral everyday order.
Η παρουσίαση αυτή is more formal/literary or used for contrast/emphasis, like “this presentation (as opposed to some other one)”.

You can do this with many nouns:

Αυτό το σπίτι / Το σπίτι αυτό = this house
Αυτές οι ιδέες / Οι ιδέες αυτές = these ideas

Why is there no μια before υπέροχη ευκαιρία? In English we say “a wonderful opportunity”.

Greek can use the indefinite article μια (“a”), but often omits it when the meaning is clear and we’re speaking in general about a kind of thing:

είναι υπέροχη ευκαιρία
≈ “(it) is a wonderful opportunity”

You could also say:

είναι μια υπέροχη ευκαιρία

Both are correct here. The version without μια sounds a bit more compact and slightly more formal, but the meaning is essentially the same.

In general:

After είμαι (“to be”), Greek can drop ένας / μία / ένα when describing someone/something:
- Είναι γιατρός. = He/She is a doctor.
- Είναι καλή ιδέα. = It’s a good idea.
- Είναι υπέροχη ευκαιρία. = It’s a wonderful opportunity.

Why does υπέροχη come before ευκαιρία? Could we say ευκαιρία υπέροχη?

The usual position of descriptive adjectives in Greek is before the noun:

υπέροχη ευκαιρία = wonderful opportunity
μεγάλο σπίτι = big house
ενδιαφέρον θέμα = interesting topic

Ευκαιρία υπέροχη is not wrong grammatically, but:

It sounds unusual and can feel poetic, very emphatic, or slightly marked.
In normal speech/writing, you’d keep it as υπέροχη ευκαιρία.

So for everyday Greek, use:

[adjective] + [noun] → υπέροχη ευκαιρία

Why is it να μιλήσω? Where is the equivalent of the English “to” in “to speak”?

Modern Greek doesn’t have an infinitive like English “to speak / to go / to see”. Instead, it uses a να-clause with a finite verb:

να μιλήσω ≈ “to speak” (literally “that I speak”)
να πάω ≈ “to go” (that I go)
να δω ≈ “to see” (that I see)

Here:

είναι υπέροχη ευκαιρία να μιλήσω…
≈ “it’s a wonderful opportunity for me to speak…”

So:

να is the “marker” introducing the verb (kind of like “to” or “that”).
μιλήσω is the verb in the subjunctive mood (1st person singular).

You’ll see να + verb in many patterns:

Θέλω να μιλήσω. = I want to speak.
Πρέπει να φύγω. = I have to leave.
Μπορώ να έρθω; = Can I come?

Why να μιλήσω and not να μιλάω? What’s the difference?

Both forms exist, but they express different aspect (a very important distinction in Greek):

να μιλήσω → aorist subjunctive: focuses on the whole action as a single event, often seen as completed or a one-off act.
να μιλάω → present subjunctive: focuses on the ongoing / repeated nature of the action.

In this sentence:

είναι υπέροχη ευκαιρία να μιλήσω ελληνικά μπροστά σε άλλους
→ suggests “a (single) chance to speak Greek (this time)”, which fits well with “opportunity”.

If you said:

…είναι υπέροχη ευκαιρία να μιλάω ελληνικά…
it would feel more like “a chance for me to be (regularly) speaking Greek”, more ongoing / repeated. Possible in some contexts, but the aorist (μιλήσω) is more natural for a specific occasion / event.

Why is the verb μιλήσω in the first person “I”? The subject of the sentence is “this presentation”.

Greek often uses να + verb to express purpose or result for a particular person, and the verb agrees with that person.

Structure here:

Main clause: Αυτή η παρουσίαση είναι υπέροχη ευκαιρία
→ This presentation is a wonderful opportunity
Purpose clause: να μιλήσω ελληνικά
→ for me to speak Greek

The subject of είναι is η παρουσίαση (the presentation).
The understood subject of μιλήσω is “I” (the speaker).

Greek doesn’t need to say εγώ (“I”) because it’s clear from the verb ending:

μιλήσω = I speak (subjunctive)
If it were “for you to speak”: να μιλήσεις
“for him/her to speak”: να μιλήσει

So the pattern is:

Είναι ευκαιρία να μιλήσω… = It’s an opportunity (for me) to speak…
Είναι ευκαιρία να μιλήσεις… = It’s an opportunity (for you) to speak…

Why is it ελληνικά and not something like ελληνική γλώσσα?

For languages, Greek very often uses the neuter plural form of the adjective as a noun:

ελληνικά (neuter plural) = Greek (language)
αγγλικά = English
γαλλικά = French
ισπανικά = Spanish

So:

Μιλάω ελληνικά. = I speak Greek.
Θέλω να μάθω αγγλικά. = I want to learn English.

You can say:

να μιλήσω την ελληνική γλώσσα
but that sounds too formal and unnatural in everyday speech. The natural idiom is simply:
να μιλήσω ελληνικά

What does μπροστά σε άλλους literally mean, and why do we use σε here?

Μπροστά σε άλλους literally is:

μπροστά = in front
σε = to / at / in
άλλους = others (masculine plural, accusative)

So μπροστά σε άλλους ≈ “in front of others (people)”.

About σε:

σε
- accusative noun is the normal way to express many relations: to, in, at, into, on, onto, etc.
Here it’s part of the fixed expression μπροστά σε = in front of.

Examples:

Μπροστά σε όλους. = in front of everyone.
Μπροστά σε παιδιά. = in front of children.

Because άλλους has no article, it just means “other people” in general:

μπροστά σε άλλους = in front of others (unspecified people)

Could we say μπροστά από άλλους or μπροστά στους άλλους? What’s the difference from μπροστά σε άλλους?

You’ll see a few variants:

μπροστά σε άλλους
- General: “in front of other people” (unspecified).
- Very natural in this sentence.
μπροστά σε άλλους ανθρώπους
- Same as (1), but explicitly “other people”.
μπροστά από άλλους
- More often suggests physical position / ahead of (“in front of others in a line, in a race, etc.”).
- In some dialects/contexts it can overlap with σε, but σε is safer here.
μπροστά στους άλλους
- With article στους (= σε + τους): “in front of the others”.
- Refers to a specific group already known in context.
- E.g. “I don’t like speaking Greek in front of the others (in my class).”

In this generic sentence, μπροστά σε άλλους is the best fit: “in front of other people (in general)”.

Why do all these words end in -η: Αυτή η παρουσίαση είναι υπέροχη ευκαιρία? Is that about gender?

Yes. Greek has grammatical gender (masculine, feminine, neuter), and adjectives, articles, and demonstratives must agree with the noun in:

gender
number
case

Here:

παρουσίαση = presentation (feminine, singular, nominative)
ευκαιρία = opportunity (feminine, singular, nominative)

So:

Αυτή = this (feminine, singular, nominative)
η = the (feminine, singular, nominative)
υπέροχη = wonderful (feminine, singular, nominative)

That’s why we have:

Αυτή η παρουσίαση
υπέροχη ευκαιρία

If the noun were masculine or neuter, the forms would change, e.g.:

Αυτός ο άνθρωπος είναι υπέροχος φίλος. (masculine)
Αυτό το βιβλίο είναι υπέροχο δώρο. (neuter)

Could we say είναι υπέροχη ευκαιρία για να μιλήσω ελληνικά instead of είναι υπέροχη ευκαιρία να μιλήσω ελληνικά?

Yes, both are possible:

είναι υπέροχη ευκαιρία να μιλήσω ελληνικά
είναι υπέροχη ευκαιρία για να μιλήσω ελληνικά

Differences:

να μιλήσω alone is slightly more direct and concise.
για να μιλήσω emphasizes the purpose a bit more explicitly (literally “for in order that I speak”), but in everyday speech the nuance is small here.

You’ll see both patterns after words like ευκαιρία, λόγος, σκοπός:

Μου δίνει ευκαιρία να μιλήσω.
Μου δίνει ευκαιρία για να μιλήσω.

In this specific sentence, the version without για is very natural and slightly smoother.