Rep je mali.

Rep means tail. It is a masculine noun in Serbian.

You can tell that mali is also in the masculine form here, because adjectives must agree with the noun they describe.

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

So:

• Rep = tail
• je = is
• mali = small

Together: The tail is small or A tail is small, depending on context.

Serbian adjectives change form to match the noun in:

• gender
• number
• case

Here, rep is:

• masculine
• singular
• nominative (because it is the subject)

So the adjective also appears in the masculine singular nominative form: mali.

Compare:

• mali rep = small tail (masculine)
• mala kuća = small house (feminine)
• malo dete = small child (neuter)

Serbian normally does not use articles like English the and a/an.

So Rep je mali can mean:

• The tail is small
• A tail is small

The exact meaning depends on context.

If Serbian speakers want to be more specific, they usually do it through context, word order, or extra words such as taj (that) or jedan (one/a certain), but there is no direct article system like in English.

The most neutral word order is:

• Rep je mali.

This is the standard subject + verb + adjective pattern.

Serbian word order is more flexible than English, so Mali je rep is possible, but it sounds more marked and would usually be used for emphasis or contrast, something like:

• The tail is small (as opposed to something else)

So for a beginner, Rep je mali is the safest and most natural basic version.

A simple pronunciation guide is:

• Rep ≈ rehp
• je ≈ yeh
• mali ≈ MAH-lee

So the whole sentence is roughly:

rehp yeh MAH-lee

A few notes:

• r in Serbian is rolled or tapped.
• j is pronounced like English y in yes.
• Serbian spelling is very phonetic, so words are usually pronounced as they are written.

You can absolutely use rep by itself if the context is clear.

For example, if you are already talking about an animal, Rep je mali naturally means Its tail is small or The tail is small.

If you want to say whose tail it is, Serbian can express that too, for example:

• Rep psa je mali. = The dog's tail is small.
• Njegov rep je mali. = His/its tail is small.

In this sentence, mali means small.

But in Serbian, mali can also sometimes mean:

• little
• young
• even something affectionate, depending on context

For example, as a noun in informal speech, mali can sometimes mean the little one, the boy, or similar, but that is a different use.

In Rep je mali, it is simply an adjective meaning small.

It is in the nominative case, because it is the subject of the sentence.

The basic dictionary form of rep is also rep, so what you see here is the normal subject form.

Since the adjective describes a nominative masculine singular noun, it also appears in the matching form: mali.

In normal present-tense standard Serbian, je is usually kept in a sentence like this:

• Rep je mali.

Leaving it out would not be standard in this kind of simple statement.

So unlike some languages where is can disappear in the present tense, Serbian normally keeps the verb to be here.

By itself, it can do either, depending on context.

Most often, a sentence like Rep je mali sounds like it refers to a specific tail already known in the conversation, because simple subject statements often work that way in context.

But since Serbian has no articles, the sentence itself does not force a strict distinction between a tail and the tail.

The verb je would stay the same in the singular, but the adjective would change to match the noun’s gender.

For example:

• Kuća je mala. = The house is small.
  (kuća is feminine, so mala)

• Dete je malo. = The child is small.
  (dete is neuter, so malo)

So in your sentence, mali tells you that rep is masculine singular.