Learn Hardcore Greek: Ναι, έχω νερό.

Interjections like Ναι (Yes) are normally followed by a comma when they begin a sentence, marking a short pause. So Ναι, έχω νερό. is the standard punctuation.

Where is the subject I in Greek? Why isn’t εγώ written?

Greek is a pro‑drop language. The verb ending in έχω already shows first person singular (I), so the subject pronoun εγώ is usually omitted unless you want emphasis (e.g., Εγώ έχω νερό, meaning I, as opposed to someone else, have water).

How do I pronounce the sentence?

Roughly: (Neh, E-ho ne-RO)

Ναι = [ne] (like English “ne” in “net” without the t)
έχω = [ˈexo]; the letter χ is a throaty fricative, like the sound in Scottish “loch”
νερό = [neˈro]; tap the ρ lightly; stress is on the final syllable

Why do έχω and νερό have accent marks but Ναι doesn’t?

Modern Greek uses one stress mark (τόνος) on stressed syllables of words with two or more syllables. έχω and νερό are disyllabic, so they take a stress mark. Ναι is monosyllabic and normally has no accent.