Kavez je u sobi.

• kavez = cage
• je = is
• u = in
• sobi = room in the form used after u for location

So the structure is very close to English: Cage is in room, with the natural translation The cage is in the room.

Je is the 3rd person singular present tense of biti = to be.

So:

• ja sam = I am
• ti si = you are
• on/ona/ono je = he/she/it is

In this sentence, kavez is singular, so Serbian uses je:
Kavez je u sobi. = The cage is in the room.

Unlike in some Slavic languages, Serbian normally does use the present-tense form of to be in sentences like this.

Because after u, Serbian changes the noun depending on the meaning.

Here, u means in, describing a location, so soba changes to the locative singular form:

• basic form: soba = room
• locative after u: u sobi = in the room

So:

• u sobi = in the room (location)
• not u soba, because soba is just the dictionary form

It is the locative singular of soba.

For many feminine nouns ending in -a, the locative singular ends in -i:

• soba → u sobi
• škola → u školi
• kuća → u kući

A very common pattern in Serbian is:

• u + locative for being in/at a place
• u + accusative for going into a place

This is an important contrast:

• u sobi = in the room → location, no movement
• u sobu = into the room → motion toward the inside

Examples:

• Kavez je u sobi. = The cage is in the room.
• Nosim kavez u sobu. = I am carrying the cage into the room.

So the case changes depending on whether you mean where something is or where something is going.

Because kavez is the subject of the sentence, so it is in the nominative case, which is the basic dictionary form.

Here:

• kavez = subject
• je = verb
• u sobi = location phrase

So kavez stays in its basic form.

It can mean either, depending on context.

Serbian does not have articles like English a/an/the. So:

• kavez can mean a cage
• kavez can also mean the cage

In a sentence like Kavez je u sobi, English usually translates it as The cage is in the room, but Serbian itself does not mark the explicitly.

Kavez is a masculine noun.

You can often tell masculine nouns because many of them end in a consonant in the basic form:

• kavez
• grad
• pas

Gender matters in Serbian because it affects things like:

• adjectives
• pronouns
• past tense forms

For example:

• veliki kavez = big cage
• novi kavez = new cage

No, Serbian word order is fairly flexible, though some orders sound more neutral than others.

Kavez je u sobi. is a neutral way to say it.

You might also hear:

• U sobi je kavez. = There is a cage in the room / The cage is in the room
• U sobi je kavez. puts more focus on where it is
• Kavez je u sobi. puts kavez more naturally as the topic

So the meaning stays similar, but the emphasis can shift.

A simple approximate pronunciation for an English speaker is:

KAH-vez yeh oo SOH-bee

A few notes:

• j in Serbian sounds like English y in yes
• e is usually like e in met, but clearer and purer
• z is like English z
• u is like oo in food
• i is like ee in see

So je sounds like yeh, not like English jee.

Yes. Serbian uses both Latin and Cyrillic scripts.

In Cyrillic, this sentence is:

Кавез је у соби.

Letter by letter:

• K = К
• a = а
• v = в
• e = е
• z = з

So Kavez je u sobi. and Кавез је у соби. are the same sentence.

Yes, in normal usage u sobi means in the room or inside the room.

Usually English just says in the room, but Serbian u clearly marks being inside that space.

If you wanted to emphasize exact interior location in English, inside the room could work, but in most contexts the standard translation is simply in the room.