Nova naušnica je mala, ali lijepa.

Because naušnica is a feminine singular noun, and the adjective has to agree with it in gender, number, and case.

So:

• novi = masculine singular
• nova = feminine singular
• novo = neuter singular

Since naušnica is feminine, you say nova naušnica.

In Croatian, many nouns ending in -a are feminine, and naušnica follows that pattern.

That is why the adjectives also take feminine forms:

• nova naušnica
• mala
• lijepa

All three adjectives are in the feminine singular form to match naušnica.

For the same reason: they must agree with naušnica, which is feminine singular.

So in this sentence:

• nova = new
• mala = small
• lijepa = beautiful

All three are feminine singular adjective forms.

Compare:

• nova naušnica je mala, ali lijepa = feminine
• novi prsten je mali, ali lijep = masculine
• novo ogledalo je malo, ali lijepo = neuter

Je means is. It is the 3rd person singular form of the verb biti (to be).

So:

• naušnica je mala = the earring is small
• je = is

Croatian often uses forms of biti just like English uses to be in sentences with adjectives.

In this sentence, no. Standard Croatian needs je here.

You can omit the subject pronoun in Croatian, but not the verb je in a normal sentence like this.

So:

• Ona je mala. = She/it is small.
• Je mala. = not normal as a full standard statement
• Naušnica je mala. = correct

Croatian does not have articles like English a/an/the.

So naušnica can mean:

• an earring
• the earring

The exact meaning depends on context.

That is very normal in Croatian, and learners often need time to get used to it.

In Croatian, adjectives often come before the noun, just like in English:

• nova naušnica = new earring
• mala kuća = small house
• lijepa žena = beautiful woman

That is the most natural position here.

Croatian word order is fairly flexible, but adjective + noun is the standard pattern.

Because ali means but, and in Croatian it is normally preceded by a comma when it joins two contrasting parts of a sentence.

So:

• mala, ali lijepa = small, but beautiful

This is standard punctuation in Croatian.

It is in the nominative singular.

You can tell because it is the subject of the sentence:

• Nova naušnica = the new earring
• je mala, ali lijepa = is small but beautiful

The nominative is the basic dictionary form of the noun.

Lijepa is the standard Croatian form, using ije.

Croatian regularly has forms like:

• lijep = beautiful
• lijepa = beautiful (feminine)
• lijepo = beautiful (neuter)

You may sometimes see lepa in other regional standards or varieties, but lijepa is the expected Croatian form.

A simple English-friendly approximation is:

NAH-oosh-nee-tsa

More carefully:

• na as in father
• uš sounds roughly like oosh
• ni like nee
• ca like tsa

So: naušnica → nah-OOSH-nee-tsa

Also:

• š sounds like sh
• c usually sounds like ts

A rough pronunciation is:

LYEH-pa

The lj sound is a special Croatian sound. It is not exactly the same as plain English l. It is a soft sound, somewhat similar to the lli in million for some English speakers.

So:

• lijepa ≈ LYEH-pa

And j in Croatian is pronounced like English y.

Yes, Croatian word order is more flexible than English, but the original order is the most neutral and natural.

Standard neutral version:

• Nova naušnica je mala, ali lijepa.

You could also hear variations for emphasis, such as:

• Mala je, ali lijepa, nova naušnica.
• Nova naušnica je lijepa, ali mala.

But those do not have exactly the same emphasis. For a learner, the original sentence is the best model to follow.

In this sentence, mala and lijepa are part of the predicate after je.

So the structure is:

• Nova naušnica = subject
• je mala, ali lijepa = predicate

This is different from:

• mala lijepa naušnica

There, the adjectives come directly before the noun and describe it inside the noun phrase. In your sentence, the speaker is making a statement about the earring: it is small, but beautiful.