Learn Hardcore Greek: Ο καναπές είναι κόκκινος και το τραπέζι είναι άσπρο.

ο καναπές – καναπές (sofa/couch) is a masculine noun, so it takes ο.
το τραπέζι – τραπέζι (table) is a neuter noun, so it takes το.

Greek nouns have grammatical gender (masculine, feminine, neuter) that must match the article and any adjectives.

Why is κόκκινος used for the sofa but άσπρο for the table?

Both κόκκινος and άσπρος mean “red” and “white” respectively, but they change form to agree with the noun’s gender, number, and case.

The basic forms are:

κόκκινος (masc.), κόκκινη (fem.), κόκκινο (neut.) = red
άσπρος (masc.), άσπρη (fem.), άσπρο (neut.) = white

In the sentence:

ο καναπές is masculine → κόκκινος (masculine form)
το τραπέζι is neuter → άσπρο (neuter form)

So the pattern is:
article + noun + adjective, and the adjective ending changes to match the noun.

Why do the adjectives κόκκινος and άσπρο come after the nouns? Can they go before, like in English?

The normal, neutral word order in Greek is:

article + noun + adjective

So:

ο καναπές είναι κόκκινος = the sofa is red
το τραπέζι είναι άσπρο = the table is white

Putting the adjective before the noun (like “red sofa”) is possible but usually needs the article repeated and often has a slightly different feel:

ο κόκκινος καναπές = the red sofa (as a phrase, e.g. “the red sofa over there”)
το άσπρο τραπέζι = the white table

In sentences with είναι (is/are), the most common pattern is noun first, then adjective:
ο καναπές είναι κόκκινος, not ο κόκκινος είναι καναπές.

What exactly is είναι? Is it like “is”? Why is it the same for both ο καναπές and το τραπέζι?

είναι is the Greek verb “to be”, equivalent to English “is/are” in the present tense.

It’s the 3rd person singular and plural form:

he is / she is / it is = είναι
they are = είναι

Greek:

ο καναπές είναι κόκκινος = the sofa is red
το τραπέζι είναι άσπρο = the table is white

So you use είναι both for singular (he/she/it) and plural (they). Context tells you which one it is.

Do I really need to repeat είναι? Could I say: Ο καναπές είναι κόκκινος και το τραπέζι άσπρο?

You can drop the second είναι, and it is still correct:

Ο καναπές είναι κόκκινος και το τραπέζι άσπρο.

This sounds quite natural, especially in speech.

However, the original sentence with είναι repeated:

Ο καναπές είναι κόκκινος και το τραπέζι είναι άσπρο.

is a bit more explicit and clear and is the most straightforward pattern for learners. Both versions are acceptable.

What does και mean, and are there any pronunciation tips?

και means “and”.

Pronunciation:

It’s pronounced like “keh” (similar to English “care” but shorter).
The αι combination here sounds like ε (short “eh” sound).

So the structure is:

Ο καναπές είναι κόκκινος και το τραπέζι είναι άσπρο.
= The sofa is red and the table is white.

Which case are ο καναπές and το τραπέζι in? How can I tell?

Both ο καναπές and το τραπέζι are in the nominative case.

You can tell because:

They are the subjects of the sentences (they are doing the “being”: they are red/white).
Their articles ο and το are nominative singular forms.

Basic singular article patterns:

Masculine: ο (nom.), τον (acc.)
Feminine: η (nom.), την (acc.)
Neuter: το (nom. and acc.)

So when you see ο καναπές or το τραπέζι at the start of a simple sentence with είναι, they are most likely nominative subjects.

Why is there an accent on καναπές and τραπέζι? Does it affect meaning or just pronunciation?

The accent in Greek words shows which syllable is stressed in pronunciation.

καναπές → stress on the last syllable: ka-na-PÉS
τραπέζι → stress on the middle syllable: tra-PÉ-zi

The accent:

Is always written in modern Greek on words of two or more syllables.
Guides pronunciation.
Can sometimes distinguish between words that are spelled the same otherwise, but here it’s mainly about correct stress.

So you must write the accent, and you must stress that syllable when speaking.

Could I drop the articles and say Καναπές είναι κόκκινος και τραπέζι είναι άσπρο?

In this kind of sentence, you normally need the articles. Without them, the sentence sounds very unnatural or wrong to a native speaker.

Greek uses the definite article much more often than English, especially with concrete, specific objects:

Ο καναπές είναι κόκκινος = The sofa is red.
Το τραπέζι είναι άσπρο = The table is white.

You might omit articles in some generic statements (e.g. Ανθρώπινη ζωή είναι πολύτιμη – “Human life is precious”), but with specific objects like the sofa and the table in a room, you keep ο / το.

Is άσπρο the only word for “white”? I’ve also seen λευκό—what’s the difference?

Greek has two common adjectives meaning white:

άσπρος, άσπρη, άσπρο
λευκός, λευκή, λευκό

In everyday speech:

άσπρος/άσπρη/άσπρο is more common and informal.
λευκός/λευκή/λευκό is more formal, or used in set phrases (e.g. λευκό κρασί = white wine).

In your sentence:

το τραπέζι είναι άσπρο is natural and conversational.
το τραπέζι είναι λευκό is also correct, but sounds a bit more formal or “neutral-standard”.

Both words must still agree in gender, number, and case with the noun.