Trebalo bi da naručimo ketering za proslavu.

In Serbian, trebati is very often used impersonally in this kind of sentence, so trebalo bi da... is extremely common and natural. Literally, it is something like it would be necessary to..., but in normal English you usually translate it as we should....

You may also hear Trebali bismo da naručimo ketering za proslavu, which is also natural. That version agrees directly with we, while trebalo bi keeps the expression more impersonal.

Bi is the conditional auxiliary. It helps create a softer, less direct meaning.

Compare:

• Treba da naručimo... = We need to / should order...
• Trebalo bi da naručimo... = We should / it would be good to order...

So bi makes the statement sound more like a suggestion than a firm necessity.

Serbian very often uses da + present-tense form where English uses an infinitive. This is one of the most common Serbian patterns.

So after words like treba, trebalo bi, mogu, želim, and moram, you will often see:

• treba da idem = I should go
• mogu da dođem = I can come
• želim da učim = I want to study

That is why trebalo bi da naručimo sounds completely normal.

After da, Serbian uses a present-tense verb form even when the action has not happened yet. The future meaning comes from the whole construction, not from the verb form by itself.

So da naručimo literally looks like a present form, but in context it means for us to order or that we order, referring here to a future action.

Naručimo comes from the perfective verb naručiti, which presents the action as a single completed event: placing the order. That fits this sentence well, because ordering catering is one concrete action.

Naručujemo would be an imperfective form, suggesting something ongoing, repeated, or habitual. That would sound less natural here unless you meant something like we are in the process of ordering or we regularly order.

It is the 1st person plural form, so it means we. It comes from the verb naručiti.

In this sentence, da naručimo means that we order or more naturally for us to order. Combined with trebalo bi, the whole idea becomes we should order.

Here ketering is the direct object, so it is in the accusative singular. But ketering is treated as a masculine inanimate noun, and for many masculine inanimate nouns, the accusative singular is the same as the nominative singular.

So:

• nominative: ketering
• accusative: ketering

In other cases, it does change. For example, the genitive is keteringa.

Because the preposition za often takes the accusative when it means for or intended for.

The noun proslava is feminine:

• nominative singular: proslava
• accusative singular: proslavu

So za proslavu means for the celebration / for the party.

Yes. Ketering is a borrowing from English catering, adapted to Serbian spelling and pronunciation. It is commonly used in everyday speech, especially when talking about events, food service, parties, and business settings.

So in this sentence, ketering sounds natural and modern, not strange or overly foreign.

Yes. Some natural alternatives are:

• Trebali bismo da naručimo ketering za proslavu.
• Treba da naručimo ketering za proslavu.
• Trebalo bi naručiti ketering za proslavu.

The meaning is similar, but the nuance changes a little:

• Trebalo bi... = softer suggestion
• Treba... = more direct, stronger necessity
• Trebalo bi naručiti... = more impersonal, like it would be good to order catering