Da-clause as an alternative to the infinitive

When you say what you must, can, want or plan to do, Serbian gives you two ways to attach the second verb. You already know the first one: the infinitive, exactly as in English I have to work. The second one has no English equivalent, and it is the one you will hear far more often in Serbia: the little word da followed by the second verb in the present tense.

The verb after da agrees with the subject

This is the whole point of the construction, and the thing to get right. After da the second verb is not a frozen dictionary form: it is a full present tense, and it takes the same person and number as the first verb. If I must, then I work: moram da radim. If you must, then you work: moraš da radiš. If the children must, then they sleep: deca moraju da spavaju. Two verbs, one subject, and both verbs show it.

It works the same with moći: mogu da idem, možeš da ideš, može da ide, možemo da idemo, možete da idete, mogu da idu. And with the infinitive, again, only the first verb moves: ne može doći beside ne može da dođe, ne možemo doći beside ne možemo da dođemo.

Never put an infinitive after da. Moram da ići is the single most common mistake learners make with this construction. Once you have said da, the next verb is in the present and agrees with the subject: moram da idem.

Which verbs take it

Any verb that is completed by another verb can take either construction. The main groups are:

• Modal verbs — morati (must), moći (can), smeti (may, be allowed), trebati (should), hteti (want), želeti (wish, want): Možeš li da mi pomogneš? — Can you help me?
• Phase verbs, which say that an action starts, stops or goes on — počinjati / početi (start), prestati (stop), nastaviti (continue): Počinjem da štedim za stan. — I'm starting to save for a flat.
• Plans and attempts — planirati (plan), nameravati (intend), pokušati (try), odlučiti (decide): Planiram da se preselim u Beograd. — I'm planning to move to Belgrade.

Wanting and planning: hoću da, želim da

This is how Serbian speakers most often talk about what they are going to do. Hoću da naučim srpski is "I want to learn Serbian", and hoćemo da otvorimo restoran is "we want to open a restaurant" — an intention, a plan. Notice that this is not the future tense: the future uses the short clitic ću with an infinitive (naučiću srpski, I will learn Serbian), while hoću da uses the full, stressed form of hteti and means want. The two sit side by side in everyday speech: Hoću da putujem, ali neću putovati ove godine — I want to travel, but I won't travel this year.

Serbia and Croatia

Both constructions are standard everywhere, but the balance differs. In Croatia the infinitive is the default and da + present sounds marked. In Serbia it is the other way round: da + present is the everyday choice and the infinitive sounds a little more formal or written. Use whichever comes to you — you will be understood and correct either way — but expect to hear da + present around you and train your ear on it.

Where the little words go

You know that clitics such as mi, ti, ga, se sit in second position in their clause. The da-clause counts as a clause of its own, and da takes the first slot, so the clitic lands immediately after it: Mogu da ti pomognem, Planiram da se preselim. With the infinitive there is only one clause and the clitic goes after the first stressed word: Mogu ti pomoći. The negative particle ne stays glued to the verb it negates, usually the first one: Ne mogu da dođem, Ne želim da ostanem.