Learn Hardcore Greek: Φεύγω τώρα, γιατί έχω ήδη φάει. - I am leaving now, because I have already eaten.

It’s the Greek present perfect, called παρακείμενος. It’s formed with the auxiliary έχω + the verb’s perfective non‑past form (the same form you see in the aorist subjunctive 3rd singular). Examples:

έχω φάει (from τρώω, perfective stem φά-)
έχω δει (from βλέπω)
έχω πάει (from πηγαίνω)
έχουμε διαβάσει (from διαβάζω)

It expresses a completed action with present relevance (which fits nicely with ήδη = already).

Could I use the simple past instead of the present perfect?

Yes. In everyday Greek, the aorist is very common for recent, completed actions:

Έφαγα ήδη.
Ήδη έφαγα. Both are natural. Έχω ήδη φάει emphasizes the result’s relevance “now,” while Έφαγα ήδη simply reports a completed past action. All are acceptable here.

Where should ήδη go in this sentence?

All of these are correct, with slight differences in emphasis:

Neutral: έχω ήδη φάει
End focus: έχω φάει ήδη
Fronted for emphasis: Ήδη έχω φάει With an object pronoun, place the pronoun before the auxiliary: Το έχω ήδη φάει.

Why use γιατί here instead of επειδή, διότι, or αφού?

γιατί = because (also “why” in questions). Neutral and common in speech. Perfect here.
επειδή = because. Slightly more careful; interchangeable: Φεύγω τώρα, επειδή έχω ήδη φάει.
διότι = because. Formal/literary; would sound stiff in casual talk.
αφού = since/as (given that). Pragmatically adds a “as is already known/obvious” flavor: Φεύγω τώρα, αφού έχω ήδη φάει.

Do I need the comma before γιατί?

Yes, typically. Greek usually places a comma before a causal clause that follows the main clause: Φεύγω τώρα, γιατί… No comma when γιατί means “why.”

What does Φεύγω τώρα convey—present or near future?

It’s present (imperfective) but often used for an imminent planned action: “I’m leaving now.” You could also say Τώρα φεύγω (stronger focus on “now”) or Θα φύγω τώρα (I’m about to leave, with a slight focus on the moment of departure).

Why is there no subject pronoun (no Εγώ)?

Greek is pro‑drop: person/number are in the verb ending, so Φεύγω already means “I am leaving.” Add Εγώ only for contrast/emphasis: Εγώ φεύγω τώρα (as for me, I’m leaving now).

How do I pronounce the tricky bits: Φεύγω, γιατί, ήδη, φάει?

Φεύγω: [ˈfevɣo] (ευ before γ sounds like “ev”; γ is a voiced velar fricative, like a soft “gh”).
γιατί: [ʝaˈti] (“ya-TEE”).
ήδη: [ˈiði] (“EE-dhi”; δ is like “th” in “this”).
φάει: [ˈfa.i] (“FA-ee,” two syllables).

Why is it φάει and not something like φάγω or φαΐ?

φάει is the perfective non‑past form used after έχω: έχω φάει.
φάγω is an older/variant form you might hear in some registers with να (e.g., να φάγω), but not in the perfect.
φαΐ (with diaeresis) is the noun “food,” not the verb form. Don’t confuse φάει (verb form) with φαΐ (noun).

Does φάει change with person in the perfect?

No. The second element is invariable; only έχω conjugates:

έχω φάει, έχεις φάει, έχει φάει, έχουμε φάει, έχετε φάει, έχουν(ε) φάει

How do I add an object pronoun (e.g., “it”)?

Place the clitic before the auxiliary:

Affirmative: Το έχω ήδη φάει.
Negative: Δεν το έχω φάει ακόμα. Avoid placing the clitic after έχω in this construction (e.g., Έχω το φάει is not natural).

Can I replace ήδη with κιόλας?

Yes, very natural and colloquial:

Φεύγω τώρα, γιατί έχω κιόλας φάει.
Έχω φάει κιόλας. ήδη is a bit more formal/neutral; κιόλας often adds a subtle “already/so soon” nuance.

Can I move τώρα elsewhere?

Yes:

Τώρα φεύγω, γιατί έχω ήδη φάει. (stronger focus on “now”)
Φεύγω τώρα… (neutral) Avoid attaching τώρα to the eating clause unless you really mean “I have eaten now,” which is unusual: …γιατί τώρα έχω ήδη φάει sounds odd.

Can I put the because‑clause first?

It’s possible but less common with γιατί: Γιατί έχω ήδη φάει, φεύγω τώρα. More natural with επειδή/αφού:

Επειδή έχω ήδη φάει, φεύγω τώρα.
Αφού έχω ήδη φάει, φεύγω τώρα.

How would I say the negative “I haven’t eaten yet”?

Use ακόμα/ακόμη for “yet” in negatives:

Δεν έχω φάει ακόμα.
Δεν έχω φάει ακόμη. Note the contrast with ήδη (already): Έχω ήδη φάει.