Pridruži nam se.

• Pridruži = join, in the imperative (a command/invitation), addressed to one person informally
• nam = to us
• se = a reflexive particle that belongs with the verb pridružiti se

So word-for-word, it is something like Join yourself to us, but in natural English it is simply Join us.

It comes from the verb pridružiti se.

That is the form you would look up in a dictionary. The sentence uses the 2nd person singular imperative of that verb:

• pridružiti se = to join
• pridruži se = join! (said to one person, informal)

Because pridružiti se is a verb that normally includes se in Serbian.

This se often does not translate directly into English. It is just part of how the verb works. Many Serbian verbs behave like this.

So you should learn it as a whole unit:

• pridružiti se = to join
• not just pridružiti

In this sentence, se does not mean yourself in a strong literal sense; it is mainly a grammatical part of the verb.

Nam is the dative form of mi (we/us).

The verb pridružiti se takes the dative:

• pridružiti se nekome = to join someone

So:

• mi = we
• nas = us (accusative/genitive)
• nam = to us (dative)

That is why Serbian says nam, not nas.

Because nam is the short, unstressed clitic form, and that is the normal choice here.

Compare:

• Pridruži nam se. = neutral, natural, everyday wording
• Pridruži se nama. = more emphatic, like Join us (not them)

So nam is the usual unstressed form, while nama is the full form used for emphasis or contrast.

Because nam and se are both clitics (short unstressed words), and Serbian has rules about where clitics go.

In a neutral sentence like this, they come right after the first stressed word, and their internal order is also fixed. Here the natural order is:

• Pridruži nam se.

Not:

• Pridruži se nam.

So this is not random word order; it follows normal Serbian clitic placement.

Pridruži is for one person informally: ti.

If you are speaking to:

• more than one person, or
• one person formally

you use:

• Pridružite nam se.

So:

• Pridruži nam se. = join us (one person, informal)
• Pridružite nam se. = join us (plural or formal)

The verb pridružiti se is perfective, and that is very natural in Serbian for a command asking for a single completed action.

So Pridruži nam se means something like:

• come and join us
• do the action of joining us

The imperfective partner is pridruživati se. Its imperative pridružuj se would sound more like repeated or ongoing joining, so it is usually not what you want for a simple invitation.

Yes. Pridruži nam se. is a very natural and common way to invite someone to become part of an activity, group, event, or conversation.

You may also see similar phrases such as:

• Pridružite nam se. = formal/plural
• Priključi nam se. = also join us, often in invitations, campaigns, online contexts, etc.

But Pridruži nam se. is absolutely standard and useful.

In Cyrillic, it is:

• Придружи нам се.

A rough pronunciation guide for an English speaker is:

• pree-DROO-zhee nahm seh

A few helpful sound notes:

• ž sounds like the s in measure
• se is seh, not English see
• Serbian r is usually tapped/trilled more than in English