Njen sin je kandidat.

Yes. Njen is the possessive pronoun meaning her.

In this sentence, njen sin means her son. Serbian uses different possessive forms depending on whose something is:

• njen = her
• njegov = his

So Njen sin is specifically her son, not his son.

Because possessive pronouns in Serbian agree with the noun they describe.

The noun here is sin (son), which is:

• masculine
• singular
• nominative

So the correct form is njen.

Compare:

• njen sin = her son
• njena ćerka = her daughter
• njeno dete = her child

So the ending changes to match the noun, not just the owner.

Yes. Njen declines, much like an adjective.

Some examples:

• njen sin = her son
• njenog sina = of her son / her son (accusative, animate)
• njenom sinu = to her son
• njenim sinom = with her son

So you should think of njen as a form that changes for gender, number, and case.

Je is the short present-tense form of biti (to be) for he/she/it is.

So in this sentence:

• sin = son
• je = is
• kandidat = candidate

It is the normal verb linking the subject and the noun that describes the subject.

Normally, no. In standard Serbian, you usually keep je in a sentence like this.

So:

• Njen sin je kandidat. = correct
• Njen sin kandidat. = not standard as a normal full sentence

Serbian does not normally drop the present-tense form of to be in this kind of statement.

Because both are in the nominative here.

• sin is the subject, so nominative is expected.
• kandidat is a predicate noun after je, and in this kind of identifying sentence it is also normally in the nominative.

That is why both words appear in their basic form:

• sin
• kandidat

Because Serbian has no articles like English a or the.

So kandidat can mean:

• a candidate
• sometimes the candidate, depending on context

Serbian leaves that distinction to context instead of using a separate article word.

Yes, Serbian word order is more flexible than English, but the neutral order here is:

Njen sin je kandidat.

You may also hear:

• Kandidat je njen sin.

That changes the emphasis, roughly like The candidate is her son or It is her son who is the candidate.

However, not every rearrangement sounds equally natural, especially because je is a short clitic form and has special placement rules. For a learner, Njen sin je kandidat is the safest normal pattern.

Yes, kandidat is a masculine noun.

Here that fits naturally, because sin refers to a male person. If the person were female, Serbian often uses kandidatkinja:

• Njena ćerka je kandidatkinja. = Her daughter is a female candidate.

That said, in real usage you may sometimes also hear kandidat used more generally, depending on style and context. But for clear learner-friendly grammar, kandidatkinja is the usual feminine form.

It is pronounced roughly like nyen.

The nj is a single sound, similar to:

• the ñ in Spanish señor
• the ny sound in English canyon

So njen is not pronounced as two separate sounds n + j in the English way. It is one combined consonant sound.