Siva mačka spava na tepihu.

Because Croatian adjectives must agree with the noun they describe in gender, number, and case.

• mačka is feminine singular
• so the adjective siv (gray) must also be in the feminine singular form: siva

Basic forms:

• siv = masculine
• siva = feminine
• sivo = neuter

So:

• siv pas = gray dog
• siva mačka = gray cat
• sivo more = gray sea

Mačka is in the nominative singular.

It is the subject of the sentence — the one doing the action:

• Siva mačka = the gray cat
• spava = sleeps

In Croatian, the subject is typically in the nominative case.

Because after the preposition na, Croatian uses different cases depending on the meaning.

Here, na tepihu means on the carpet in the sense of location (where the cat is sleeping), so tepih goes into the locative singular:

• nominative: tepih
• locative: tepihu

So:

• na tepihu = on the carpet

A very useful contrast is:

• Mačka je na tepihu. = The cat is on the carpet.
• Mačka skače na tepih. = The cat jumps onto the carpet.

In the second sentence, there is movement toward a destination, so Croatian uses a different case.

Not always. Na often means on, but it can also mean things like at or to, depending on context.

Examples:

• na stolu = on the table
• na poslu = at work
• na more = to the seaside / to the sea

In Siva mačka spava na tepihu, the meaning is clearly on because it describes physical location.

Croatian normally does not use articles like English a/an or the.

So:

• mačka can mean a cat or the cat
• context tells you which one is meant

That means Siva mačka spava na tepihu could be understood as:

• The gray cat is sleeping on the carpet or
• A gray cat is sleeping on the carpet

English requires an article, but Croatian usually does not.

Spava is the 3rd person singular present tense of the verb spavati (to sleep).

So:

• spavati = to sleep
• spavam = I sleep / am sleeping
• spavaš = you sleep
• spava = he/she/it sleeps

Because the subject is mačka (cat), which is third person singular, the verb is spava.

Yes. That would simply mean The/A cat is sleeping on the carpet.

The adjective siva is just extra information describing the cat:

• Mačka spava na tepihu. = The cat is sleeping on the carpet.
• Siva mačka spava na tepihu. = The gray cat is sleeping on the carpet.

No, Croatian word order is more flexible than English word order.

The neutral, straightforward order here is:

• Siva mačka spava na tepihu.

But other orders are possible, depending on emphasis:

• Na tepihu spava siva mačka. = On the carpet, a gray cat is sleeping.
• Spava siva mačka na tepihu. = possible, but more marked or literary

English depends heavily on word order to show grammatical roles. Croatian relies much more on case endings, so word order can shift for emphasis, style, or focus.

Grammatically, mačka is a feminine noun.

That means adjectives and some other words must match it as feminine:

• siva mačka
• not siv mačka

In meaning, mačka often refers to a female cat, but in everyday speech it can also be used more generally for cat. If you specifically mean a male cat, Croatian often uses mačak.

So:

• mačka = cat / female cat
• mačak = tomcat / male cat

A few pronunciation points are especially useful here:

• č is pronounced like ch in chocolate
• c in Croatian is pronounced like ts in cats
• Croatian words are usually pronounced quite consistently as written

Approximate pronunciation:

• siva ≈ SEE-va
• mačka ≈ MATCH-ka
• spava ≈ SPA-va
• na ≈ na
• tepihu ≈ TEH-pee-hoo

So the whole sentence is roughly:

• SEE-va MATCH-ka SPA-va na TEH-pee-hoo

This is a very important Croatian pattern:

• na + locative = location, where something is
• na + accusative = movement toward something

So:

• na tepihu = on the carpet
• na tepih = onto the carpet

Compare:

• Mačka spava na tepihu. = The cat is sleeping on the carpet.
• Mačka skače na tepih. = The cat jumps onto the carpet.

English often uses different prepositions like on vs onto. Croatian often shows this distinction through case.

No. In this sentence, the noun mačka is already the subject, so no pronoun is needed.

Croatian often leaves pronouns out unless they are needed for emphasis or contrast.

So:

• Siva mačka spava na tepihu. = perfectly natural
• Ona spava na tepihu. = She is sleeping on the carpet
• Siva mačka, ona spava na tepihu. = possible, but now ona adds emphasis and is usually unnecessary

In normal Croatian, explicit subject pronouns are used much less often than in English.