Obje djevojke su spremne.

Obje means both.

Croatian changes this word to match gender:

• oba = masculine or some neuter uses
• obje = feminine

Because djevojke is a feminine plural noun, Croatian uses obje.

So:

• oba dječaka = both boys
• obje djevojke = both girls

The basic singular form is djevojka.

Here, it becomes djevojke because it is plural and it is the subject of the sentence, so it is in the nominative plural.

A quick comparison:

• djevojka = girl
• djevojke = girls

In this sentence, obje djevojke is the full subject: both girls.

Spremne is an adjective meaning ready, and in Croatian adjectives must agree with the noun they describe.

Since the sentence is about djevojke:

• feminine
• plural

the adjective also has to be feminine plural:

• spremna = ready, feminine singular
• spremne = ready, feminine plural

So djevojke su spremne uses matching feminine plural forms.

Su is the 3rd person plural present tense of biti (to be).

So it means are.

A few forms of biti in the present tense:

• sam = am
• si = are
• je = is
• smo = are
• ste = are
• su = are

Because the subject is plural (both girls), Croatian uses su.

Croatian word order is fairly flexible, but Obje djevojke su spremne is a very natural, neutral way to say it.

This order is easy to understand:

• Obje djevojke = subject
• su = are
• spremne = ready

Other orders are sometimes possible for emphasis, but they may sound more marked or literary. For a learner, this sentence is the safest standard pattern.

This is an important difference:

• obje djevojke = both girls
• dvije djevojke = two girls

Obje implies a specific pair, and both members of that pair are included.

So if there are two girls you already have in mind, obje is the right word. If you are just stating the number, dvije means two.

Yes, if the context is already clear.

For example:

• Obje su spremne. = Both are ready.

In that case, obje works almost like both of them. Croatian often leaves out the noun when it is obvious from context.

Not always. Djevojka can mean:

• girl
• young woman
• sometimes girlfriend, depending on context

So the exact meaning depends on the situation. In a sentence like this, it is usually understood as girls or young women, unless the context clearly points to girlfriends.

A rough English-friendly guide:

• djevojke ≈ dye-VOY-keh
• spremne ≈ SPREM-neh

A few helpful pronunciation points:

• j in Croatian sounds like English y
• dj in djevojke is a soft sound, roughly like dy
• stress in djevojke is roughly on voj
• e is usually a clear eh sound, not a reduced English schwa

This is only an approximation, but it is good enough to get started.

If you were talking about one girl, you would say:

• Djevojka je spremna. = The girl is ready.

Compare the changes:

• djevojka → djevojke
• je → su
• spremna → spremne

So Croatian changes the noun, the verb, and the adjective to match singular or plural.