Η φυλή είναι άγνωστη.

Η is the definite article for a feminine singular noun in the nominative case.

So in Η φυλή, both words are feminine singular nominative:

• Η = the
• φυλή = the noun

A learner often notices that Greek articles change a lot. Here the article matches the noun’s gender, number, and case.

φυλή is feminine.

One clue is the article Η. Another clue is the ending -ή, which is very often feminine in Greek.

In this sentence:

• Η φυλή = feminine singular

Because the noun is feminine, any adjective describing it also has to be feminine.

Because adjectives in Greek must agree with the noun they describe.

Since φυλή is:

• feminine
• singular
• nominative

the adjective must also be:

• feminine
• singular
• nominative

So:

• masculine: άγνωστος
• feminine: άγνωστη
• neuter: άγνωστο

Here we need άγνωστη to match φυλή.

It is in the nominative case.

That is because φυλή is the subject of the sentence, and subjects are normally in the nominative in Greek.

Also, after είναι, the predicate adjective άγνωστη stays in the nominative too:

• Η φυλή = nominative subject
• είναι = is
• άγνωστη = nominative predicate adjective

In this kind of standard sentence, Greek normally uses the verb είναι.

So:

• Η φυλή είναι άγνωστη. = correct, normal full sentence

In some informal contexts, especially in headlines, notes, or very casual speech, Greek may sometimes omit είναι, but for learners, the safe rule is:

Keep the verb.

So if you want to say The breed is unknown, you should use είναι.

It is an adjective meaning unknown.

In this sentence it comes after the verb είναι, so it works as a predicate adjective:

• Η φυλή είναι άγνωστη.
• literally: The breed is unknown.

Compare that with an adjective directly before the noun:

• η άγνωστη φυλή = the unknown breed/tribe

So Greek can use the same adjective:

• attributively: directly with the noun
• predicatively: after είναι

The dictionary form is usually the masculine singular nominative:

• άγνωστος (masculine)
• άγνωστη (feminine)
• άγνωστο (neuter)

So if you look it up, you will usually find άγνωστος.

A useful thing to notice is the pattern:

• γνωστός = known
• άγνωστος = unknown

The prefix α- here gives a negative sense.

A rough pronunciation is:

ee fee-LEE EE-ne agh-NOH-stee

More carefully:

• Η = ee
• φυλή = fee-LEE
• είναι = EE-ne
• άγνωστη = AGH-no-stee

A few helpful notes:

• η sounds like ee
• υ also sounds like ee in Modern Greek
• ει also sounds like ee
• γν in άγνωστη may feel unusual to English speakers; the γ is softer than English g

So this short sentence contains several different spellings that all sound like ee.

That is a very common question in Greek.

In this sentence alone, you can see several spellings for the ee sound:

• Η
• υ in φυλή
• ει in είναι

In Modern Greek, these are pronounced the same or nearly the same: /i/.

This happened because over time several older vowel sounds merged in pronunciation. Greek spelling still preserves the older distinctions, so learners have to get used to the fact that:

• different spellings
• same modern sound

Because that is simply where the word is accented: φυλή.

Stress matters in Greek, and it is marked with an accent mark:

• φυλή → stress on the last syllable
• άγνωστη → stress on the first syllable
• είναι → stress on the first syllable

So when reading Greek, always pay attention to the accent mark, because it tells you which syllable to stress.

Yes, Greek word order is more flexible than English.

The neutral, standard order is:

• Η φυλή είναι άγνωστη.

But you may also see:

• Άγνωστη είναι η φυλή.

That changes the focus or emphasis, something like:

• Unknown is the breed
• or It is the breed that is unknown

For learners, the original order is the safest and most natural one to produce.

Because here άγνωστη is not being used as a noun phrase by itself. It is a predicate adjective after είναι.

So Greek says:

• Η φυλή είναι άγνωστη.

Not:

• Η φυλή είναι η άγνωστη. unless you mean something very different and very specific

After είναι, adjectives usually appear without an article when they simply describe the subject.

Yes. φυλή can have different meanings depending on context, such as:

• tribe
• race (in some contexts)
• breed (for animals)

So the grammar of the sentence stays the same, but the best English translation may change depending on what you are talking about.

That is very common in Greek vocabulary: one word may cover several related meanings, and context tells you which one is intended.

Usually, Greek does not use an indefinite article the same way English uses a/an.

Greek often expresses indefiniteness with:

• no article at all, or
• the word ένας / μία / ένα when needed for emphasis or clarity

But in your sentence, the noun is definite:

• Η φυλή = the breed

So the article is there because the sentence is about a specific breed, not just any breed.

A very useful pattern is:

[definite article + noun] + είναι + [matching adjective]

Here:

• Η φυλή = article + noun
• είναι = is
• άγνωστη = adjective matching the noun

You can build many similar sentences:

• Η πόλη είναι μεγάλη. = The city is big.
• Η απάντηση είναι σωστή. = The answer is correct.
• Η λέξη είναι δύσκολη. = The word is difficult.

So this sentence is a good model for learning:

1. article-noun agreement
2. adjective agreement
3. the use of είναι in simple statements