Ο σκύλος μου είναι πολύ γρήγορος.

Breakdown of Ο σκύλος μου είναι πολύ γρήγορος.

είμαι
to be
πολύ
very
μου
my
ο σκύλος
the dog
γρήγορος
quick
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Questions & Answers about Ο σκύλος μου είναι πολύ γρήγορος.

Why does the sentence start with Ο? In English we just say “my dog”, without “the”.

In Greek, when you say “my X,” you almost always use the definite article:

  • ο σκύλος μου = the dog my → “my dog”
  • η μητέρα μου = the mother my → “my mother”
  • το σπίτι μου = the house my → “my house”

So the normal pattern is:

article + noun + possessive pronoun
ο / η / το + noun + μου / σου / του / της / μας / σας / τους

Ο here is the masculine singular nominative article “the,” matching σκύλος (a masculine noun). Even though English doesn’t say “the” in “my dog,” Greek grammar requires it.

Why is μου after σκύλος instead of before it, like “my dog”?

Greek uses a different word order for possessives than English.

  • English: my dogmy + noun
  • Greek: ο σκύλος μουthe dog my

The little word μου is a clitic pronoun in the genitive case, meaning “of me / my.” It almost always comes after the noun it belongs to:

  • ο φίλος μου – my friend
  • η δασκάλα μου – my teacher
  • το βιβλίο μου – my book

You can say ο δικός μου σκύλος (“my own dog / the dog that is mine”), but that changes the structure and adds emphasis. The neutral, everyday way is ο σκύλος μου.

What exactly is είναι? Does it mean “is”?

Yes. Είναι is the present tense form of the verb είμαι (to be). It corresponds to English “is/are.”

It’s used for he / she / it is and they are:

  • είμαι – I am
  • είσαι – you are (singular)
  • είναι – he / she / it is
  • είμαστε – we are
  • είστε – you are (plural / polite)
  • είναι – they are

So in:

Ο σκύλος μου είναι πολύ γρήγορος.
“My dog is very fast.”

είναι is “is,” agreeing with the subject ο σκύλος μου (my dog).

Why is πολύ used here? What does it do exactly?

Πολύ here is an adverb meaning “very.” It modifies the adjective γρήγορος (“fast”):

  • γρήγορος – fast
  • πολύ γρήγορος – very fast

As an adverb, πολύ does not change form; it stays πολύ no matter the gender or number:

  • πολύ γρήγορος – very fast (masculine)
  • πολύ γρήγορη – very fast (feminine)
  • πολύ γρήγορο – very fast (neuter)

Be careful: πολύς / πολλή / πολύ (with endings changing) are the adjective forms meaning “much / many.” Here we are using the adverb “very.”

Why does γρήγορος end in -ος? Does that mean it’s masculine?

Exactly. Γρήγορος is an adjective meaning “fast, quick,” and Greek adjectives must agree in gender, number, and case with the noun they describe.

The noun:

  • ο σκύλος – masculine, singular, nominative

So the adjective must also be:

  • γρήγορος – masculine, singular, nominative

Typical forms for γρήγορος (singular nominative):

  • Masculine: γρήγορος (for ο σκύλος – the dog)
  • Feminine: γρήγορη (for η γάτα – the cat)
  • Neuter: γρήγορο (for το αυτοκίνητο – the car)

So:

  • Ο σκύλος μου είναι πολύ γρήγορος. – My (male) dog is very fast.
  • Η γάτα μου είναι πολύ γρήγορη. – My (female) cat is very fast.
  • Το αυτοκίνητό μου είναι πολύ γρήγορο. – My car is very fast.
Why doesn’t γρήγορος have an article (“the fast”)?

Because here γρήγορος is a predicate adjective (it’s part of what is said about the subject via the verb “to be”), not a regular noun phrase.

Greek usually omits the article before a predicate adjective that just describes the subject:

  • Ο σκύλος μου είναι γρήγορος. – My dog is fast.
  • Η Μαρία είναι έξυπνη. – Maria is smart.
  • Το σπίτι είναι μεγάλο. – The house is big.

If you add an article to the adjective (e.g. είναι ο γρήγορος), it usually sounds like you’re identifying a specific “fast one” in contrast to other possibilities, not just giving a simple description. That’s not what’s happening here; we just mean “is very fast.”

Why is σκύλος masculine? I thought σκυλί is “dog” too.

Both are correct Greek words for “dog,” but they’re different genders and styles:

  • ο σκύλος – masculine noun, often a bit more “formal / standard”
  • το σκυλί – neuter noun, very common in everyday speech

Examples:

  • Ο σκύλος μου είναι πολύ γρήγορος. – My dog (masc.) is very fast.
  • Το σκυλί μου είναι πολύ γρήγορο. – My dog (neut.) is very fast.

Notice how the adjective changes to match the noun:

  • ο σκύλοςγρήγορος
  • το σκυλίγρήγορο

Meaning-wise in modern Greek, they’re both just “dog,” though context and style can affect which one sounds more natural.

Could I say “Ο σκύλος μου είναι γρήγορος πολύ” instead of “πολύ γρήγορος”?

The normal, most natural way is:

είναι πολύ γρήγορος

Adverbs like πολύ usually come before the adjective they modify.

πολύ + adjective

“γρήγορος πολύ” is possible in some contexts, usually with a different rhythm or emphasis, but in everyday neutral speech it often sounds a bit poetic, old-fashioned, or emphatic, not like a standard learner sentence. So for now, stick to:

  • Ο σκύλος μου είναι πολύ γρήγορος.
Can I omit είναι, like in some other languages (“My dog very fast”)?

In standard modern Greek, you normally do not omit the verb είναι in this kind of sentence. You should say:

  • Ο σκύλος μου είναι πολύ γρήγορος.

Dropping είναι (Ο σκύλος μου πολύ γρήγορος) sounds ungrammatical in normal speech, except in very special contexts (headlines, notes, telegraphic style, some fixed expressions).

So: always include είναι when you’re forming a regular sentence like this.

How do you pronounce Ο σκύλος μου είναι πολύ γρήγορος?

Approximate pronunciation in Latin letters:

[o SKI-los mu Í-ne po-LÍ GRÍ-go-ros]

Syllable by syllable with stress (’ marks the stressed syllable):

  • Οo (like “o” in “hot,” but shorter)
  • σκύ-λοςSKÝ-los (stress on σκύ; υ here sounds like “ee”)
  • μουmu (like “moo” in English, but shorter)
  • εί-ναιÍ-ne (stress on εί, sounds like “EE”; final -αι sounds like “e” in “set”)
  • πο-λύpo-LÝ (stress on λύ; “po” like “po” in “pot”)
  • γρή-γο-ροςGRÍ-go-ros (stress on γρή; Greek γ before ρ / ο is a soft “g,” somewhat like a voiced “gh”)

Main stresses: σκύ, εί, λύ, γρή.

What’s the difference between ο σκύλος μου and το σκυλί μου in meaning?

Both can usually be translated as “my dog.”

  • ο σκύλος μου – masculine; a bit more “standard / formal.”
  • το σκυλί μου – neuter; very widely used in everyday speech.

Sometimes σκυλί can sound slightly more neutral or affectionate, but in modern Greek the difference is mostly grammatical (gender) and stylistic, not a big difference in meaning. When you change the noun, you must also change agreeing words:

  • Ο σκύλος μου είναι πολύ γρήγορος.
  • Το σκυλί μου είναι πολύ γρήγορο.
Why is it σκύλος here and not σκύλο?

Greek nouns change form according to case. Here, ο σκύλος is the subject of the sentence, so it’s in the nominative case:

  • (Ο) σκύλος – nominative (subject form)
  • (Τον) σκύλο – accusative (object form)

Examples:

  • Ο σκύλος μου είναι πολύ γρήγορος.My dog is very fast. (subject → σκύλος)
  • Βλέπω τον σκύλο μου.I see my dog. (object → σκύλο)

So in your sentence, because “my dog” is the subject, we use σκύλος, not σκύλο.