Learn Hardcore Greek: Έχω έναν μεγάλο σκύλο στο σπίτι.

In this sentence, Έχω έναν μεγάλο σκύλο στο σπίτι = “I have a big dog at home.”
The verb έχω takes a direct object (“what do I have?” → “a big dog”), which is why σκύλο is in the accusative case.

Why is it έχω and not είμαι (I am)?

Greek, like English, uses “have” (έχω) to talk about possession, not “be” (είμαι).

Έχω έναν σκύλο. = I have a dog.
Είμαι ένας σκύλος. = I am a dog. (completely different meaning)

So to say you own/possess a dog, you must use έχω, not είμαι.

Why is it έναν and not ένα before μεγάλο σκύλο?

Έναν is the masculine accusative singular form of the indefinite article “a/an”.

Masculine nominative: ένας (subject)
Masculine accusative: έναν / ένα (object)

Because σκύλο is masculine and is the direct object (accusative), the article also has to be masculine accusative:

έναν μεγάλο σκύλο = a big (male) dog

You will also hear ένα μεγάλο σκύλο in everyday speech.
Both are understood, but έναν μεγάλο σκύλο is more formal / careful.

Why is it σκύλο and not σκύλος?

Σκύλος is the nominative form (used for the subject of the sentence).
Here, the dog is not the subject; it is the object of the verb “have”:

Έχω τι; → έναν μεγάλο σκύλο (What do I have? → a big dog)

For direct objects, Greek uses the accusative case:

Nominative: ο σκύλος = the dog (subject)
Accusative: το σκύλο = the dog (object)

So we say: Έχω έναν μεγάλο σκύλο.

What gender is σκύλος, and how does that affect the sentence?

Σκύλος is masculine in Greek. This affects:

The article:
- έναν (masculine accusative “a”)
The adjective:
- μεγάλο is the masculine accusative form of μεγάλος (big)

All three must agree in gender and case:

έναν (masc. acc.)
μεγάλο (masc. acc.)
σκύλο (masc. acc.)

They form one noun phrase: έναν μεγάλο σκύλο = a big dog.

Why is the adjective μεγάλο in that form and placed before σκύλο?

Μεγάλο is the accusative masculine singular form of the adjective μεγάλος (big).
It must match (agree with) σκύλο in:

Gender: masculine
Number: singular
Case: accusative

Basic pattern with an indefinite article is:

article – adjective – noun

So:

έναν μεγάλο σκύλο = a big dog

You can sometimes find the adjective after the noun (έναν σκύλο μεγάλο), but the most common neutral order with an article is article–adjective–noun as in the sentence.

What exactly does στο mean in στο σπίτι?

Στο is a contraction of two words:

σε (in, at, to)
το (the – neuter singular)

So:

σε + το σπίτι → στο σπίτι

Literally: “in/at the house”.

In this sentence, στο σπίτι means “at home” or “in the house”, depending on context.

Is στο σπίτι closer to “at home” or “in the house”?

Literally, στο σπίτι = “in/at the house”.

In practice:

Έχω έναν μεγάλο σκύλο στο σπίτι.
→ Often understood as “I have a big dog at home.” (where you live)

If you strongly want the idea of “inside the building”, context or extra words may be added, but στο σπίτι already commonly works for both “at home” and “in the house”.

Why is there no separate word for “a” before σπίτι in στο σπίτι?

There actually is an article, but it is inside στο:

στο σπίτι = σε + το σπίτι = in/at the house (with “the”, not “a”)

So the sentence literally has:

έναν = a (before σκύλο)
το (inside στο) = the (before σπίτι)

If you wanted “in a house”, you would say σε ένα σπίτι (not contracted), but that’s unusual in this “home” sense.

Can I change the word order, for example say Στο σπίτι έχω έναν μεγάλο σκύλο?

Yes. Greek word order is quite flexible. All of these are possible:

Έχω έναν μεγάλο σκύλο στο σπίτι.
Στο σπίτι έχω έναν μεγάλο σκύλο.
Έναν μεγάλο σκύλο έχω στο σπίτι.

They all mean essentially “I have a big dog at home,” but the emphasis shifts:

Starting with Στο σπίτι highlights the place:
- Στο σπίτι έχω έναν μεγάλο σκύλο → “At home, I have a big dog (maybe not elsewhere).”
Starting with Έναν μεγάλο σκύλο highlights the dog:
- Έναν μεγάλο σκύλο έχω στο σπίτι → “A big dog I have at home (not a small one).”

The original Έχω έναν μεγάλο σκύλο στο σπίτι is the most neutral.

How do you pronounce the sentence, and what do the accents do?

Sentence:
Έχω έναν μεγάλο σκύλο στο σπίτι.

Approximate pronunciation (in English-like spelling):

Έχω → E-ho (EH-ho)
έναν → E-nan (EH-nan)
μεγάλο → me-GA-lo (meh-GAH-lo)
σκύλο → SKI-lo (SKEE-lo, with “k” sound)
στο → sto (sto)
σπίτι → SPEE-tee (SPEE-tee)

The little accent mark (´) in Greek shows which syllable is stressed:

Έχω
εΝΑΝ
μεΓΑλο
ΣΚΥλο
ΣΠΙτι

Stress is important in Greek; putting it on the wrong syllable can make words sound unnatural or even be misunderstood.

Are there alternative correct ways to say “I have a big dog at home” in Greek?

Yes, some natural variations include:

Έχω ένα μεγάλο σκύλο στο σπίτι.
- Using ένα instead of έναν (common in speech).
Στο σπίτι έχω έναν μεγάλο σκύλο.
- Same words, different emphasis (focus on “at home”).
Έχω έναν πολύ μεγάλο σκύλο στο σπίτι.
- “I have a very big dog at home.” (adding πολύ = very).

All of these are grammatically correct; the basic structure of your original sentence is already natural and correct.