Learn Hardcore Greek: Χτες αγόρασα καφέ, αλλά σήμερα δεν αγοράζω τίποτα. - Yesterday I bought coffee, but today I am not buying anything.

χτες/χθες: both common; χθες is a bit more formal.
εχτές/εχθές: also used; εχθές feels more formal. In monotonic Greek, one‑syllable words do not take an accent mark, so χτες appears without an accent. The two‑syllable forms (εχτές/εχθές) take an accent as usual.

Why is αγόρασα used in the first clause but αγοράζω in the second? What’s the difference?

αγόρασα is the aorist (simple past): a single, completed event in the past.
αγοράζω is the present: used for general present time, habits, and also for what English would call the present progressive (“I’m buying”/“I’m not buying”). Here it contrasts a completed past action (yesterday) with a present/ongoing stance (today).

How is αγόρασα different from αγόραζα?

αγόρασα (aorist): one completed event (“I bought” once).
αγόραζα (imperfect): past ongoing/habitual (“I was buying,” “I used to buy”). The sentence needs αγόρασα because it refers to a single event yesterday.

Could I say “σήμερα δεν θα αγοράσω τίποτα” instead of “σήμερα δεν αγοράζω τίποτα”? What’s the nuance?

Yes.

δεν αγοράζω today = a present decision/plan or general stance for today.
δεν θα αγοράσω = a future decision/promise about the rest of today or a specific future time. Both work; the first feels more like an ongoing plan, the second like a decision about what will (not) happen.

Why is there no article before καφέ? Shouldn’t it be έναν καφέ?

Greek often drops the article with food/drink after verbs like want/buy/get:

αγόρασα καφέ can mean “I bought coffee” (some coffee) or even “I bought a coffee” in everyday speech. If you want to be explicit:
αγόρασα έναν καφέ = one coffee (a cup).
αγόρασα τον καφέ = the specific coffee we both know about.

What form is καφέ here?

It’s the accusative singular of the noun ο καφές (masculine).

Nom.: ο καφές
Acc.: τον καφέ → after a verb: αγόρασα καφέ Note: καφέ is also the word for “café” (the place), neuter and indeclinable with το (το καφέ), but here it’s clearly the drink.

Is “δεν … τίποτα” a double negative? Why is nothing expressed with two negatives?

Greek has negative concord: a negative verb typically pairs with a negative/indefinite like τίποτα.

δεν αγοράζω τίποτα = “I am not buying anything.” Using only one of them (e.g., δεν αγοράζω κάτι) changes the meaning to “I’m not buying something (in particular),” which is odd unless you’re contrasting with something else.

Can I use τίποτε instead of τίποτα? And what about in questions?

Yes—τίποτε is a stylistic/variant form of τίποτα; τίποτα is more common.

With δεν: δεν αγοράζω τίποτα = I’m buying nothing.
In questions: Αγοράζεις τίποτα; = “Are you buying anything?” (informal, often expecting “maybe”). So τίποτα means “anything” in questions and “nothing” with a negative.

Why do we use δεν and not μην?

δεν negates indicative statements (facts): δεν αγοράζω, δεν πήγα, δεν θέλω.
μην negates the subjunctive/imperatives or after να/ας: να μην αγοράσεις, μην αγοράσεις! Here we have a plain statement, so δεν is correct.

Where does δεν go in the sentence? Can it move?

δεν comes right before the verb (and any clitics): δεν αγοράζω, δεν το αγοράζω. You can front τίποτα for emphasis: Σήμερα τίποτα δεν αγοράζω, but δεν still stays before the verb.

Can I move χτες and σήμερα around, and what changes?

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

Αγόρασα καφέ χτες, αλλά σήμερα δεν αγοράζω τίποτα.
Σήμερα δεν αγοράζω τίποτα, αλλά χτες αγόρασα καφέ. Moving the time adverbs shifts emphasis to what you put earlier, but the meaning remains the same.

Should there be a comma before αλλά?

Yes. In Greek, αλλά (but) usually takes a comma before it when connecting clauses: …, αλλά …

Why does the stress move from αγοράζω to αγόρασα?

Different tenses follow different accent patterns. Verbs in -άζω typically shift stress in the aorist:

Present: αγοράζω
Aorist: αγόρασα You don’t need to compute it; just learn the pairings—this pattern is regular for many -άζω verbs.

How do I pronounce the tricky sounds here?

χ in χτες: like German/Scottish “ch” (Bach/loch). Before front vowels it’s lighter (here it’s before a consonant).
γ in αγόρασα/αγοράζω: a soft, voiced sound [ɣ], not a hard English “g.”
ου/ο/ω here are simple “o” sounds; φέ in καφέ is stressed “fe.”
τί in τίποτα is stressed “TEE,” and the final -τα is “ta.”

Could I use παίρνω instead of αγοράζω?

Yes. Παίρνω is very common colloquially for getting/buying:

Χτες πήρα καφέ, αλλά σήμερα δεν παίρνω τίποτα. αγοράζω focuses on the act of purchasing; παίρνω is broader (“get/grab/buy” depending on context).

How do I say “no coffee at all” specifically?

Use καθόλου with a noun:

Σήμερα δεν αγοράζω καθόλου καφέ. = not buying any coffee at all. With things in general: Δεν αγοράζω τίποτα = I’m not buying anything (nothing at all).

Can I use the perfect, like έχω αγοράσει, with χτες?

Normally no. The Greek perfect (έχω αγοράσει) describes a present state/result and usually doesn’t pair with specific past time adverbs like χτες. For a specific past time (“yesterday”), use the aorist: αγόρασα.

Is writing δε instead of δεν okay?

In careful/standard writing, keep δεν. In informal writing and speech, people often say/write δε before consonants (e.g., δε θέλω). Both are understood; δεν is the safe default.