Δεν προλαβαίνω να φτάσω στη διάλεξη, γιατί έχει πολλή κίνηση.

Προλαβαίνω means “to make it in time / to manage to do something before it’s too late.”
So Δεν προλαβαίνω is “I can’t make it (in time)” / “I won’t have time.”

It’s very common in speech for time pressure:

• Δεν προλαβαίνω να έρθω. = I can’t make it / I won’t have time to come.
• Προλαβαίνουμε; = Can we make it (in time)?

Greek typically uses να + verb (the “subjunctive” structure) after many verbs to express what you’re trying/able/forced to do.
With προλαβαίνω, the pattern is:

• (Δεν) προλαβαίνω να + verb = (I don’t) manage to + verb / (I don’t) have time to + verb

Here: Δεν προλαβαίνω να φτάσω = “I can’t make it to arrive (in time).”

φτάσω is the aorist subjunctive of φτάνω (“to arrive”).
After να, Greek chooses between:

• aorist subjunctive (single completed event): να φτάσω = “to arrive” (once)
• present subjunctive (ongoing/repeated): να φτάνω = “to be arriving / to arrive regularly”

Since arriving at the lecture is a single event, να φτάσω is the natural choice.

φτάνω can be used with a destination:

• φτάνω + σε + place = “arrive at/to (a place)”

So να φτάσω στη διάλεξη literally means “to arrive at the lecture.” In English we often say “get to the lecture/class.”

στη is a very common contraction:

• σε + τη(ν) → στη

So στη διάλεξη = “to/at the lecture” (feminine singular).
Similarly:

• στο = σε + το (neuter)
• στον = σε + τον (masculine)

διάλεξη means “lecture” (a talk/lesson, often in a university context).
Other related words:

• μάθημα = “lesson/class” (more general)
• τάξη = “classroom” or “school class (group)” So this sentence specifically implies a lecture-type event.

Yes. γιατί can mean:

• because (giving a reason)
• why (asking a question)

In this sentence it’s clearly because:
..., γιατί έχει πολλή κίνηση. = “..., because there’s a lot of traffic.”

If it were a question (“why?”), intonation and/or punctuation would show it:

• Γιατί έχει πολλή κίνηση; = “Why is there so much traffic?”

Greek often expresses “there is traffic” with έχει κίνηση (“it has traffic”), an idiomatic construction. It’s extremely common.

You can also say:

• Υπάρχει πολλή κίνηση. = “There is a lot of traffic.” (more formal/neutral) But έχει κίνηση is the everyday default.

κίνηση literally means “movement,” but in everyday Greek (πολλή) κίνηση commonly means traffic / congestion (especially on roads).
So έχει πολλή κίνηση = “there’s heavy traffic.”

Because κίνηση is feminine singular, and adjectives agree in gender/number/case.

• Feminine singular: πολλή κίνηση
• Neuter singular: πολύ νερό (“a lot of water”)
• Masculine singular: πολλός κόσμος (“a lot of people”)

It’s common and usually appropriate when γιατί introduces an explanatory reason clause, especially in writing:

• Δεν προλαβαίνω..., γιατί...

In informal texting, people may omit punctuation, but in standard writing the comma is normal.

A rough pronunciation guide (not IPA, but helpful):

• Δεν ≈ “then” (with th as in this)
• προλαβαίνω ≈ pro-la-va-EE-no
• να φτάσω ≈ na FTA-so (the ft cluster is one of the tricky parts)
• στη ≈ stee
• διάλεξη ≈ THEE-a-le-xee (with th as in this)

Key stress points: προλαβαίνω, φτάσω, διάλεξη, πολλή, κίνηση.

Yes, Greek word order is flexible. You can say:

• Γιατί έχει πολλή κίνηση, δεν προλαβαίνω να φτάσω στη διάλεξη.
  That sounds a bit more “setting the reason first,” but it’s completely natural.