Here's why these verbs are worth a page of their own: they don't work alone. A modal verb sets the mood — possibility, obligation, desire — and then hands off to a second verb that carries the actual action. Mogu ("I can") is a promise of nothing until you say mogu da pomognem ("I can help"). Get the five modals below solid, learn the single joining rule, and a huge amount of real conversation opens up at once.
The five you actually need
These are ekavian (Serbian) spellings; the ijekavian side — Montenegro and Croatia — swaps two of them for htjeti and smjeti, and nothing else changes. Say the part in capitals a touch louder.
| Verb | Say it | Meaning | "I" form |
|---|
| moći | MO-tchi | can, to be able | mogu |
| morati | MO-ra-ti | must, to have to | moram |
| hteti | HTE-ti | to want (also builds the future) | hoću |
| smeti | SME-ti | may, to be allowed | smem |
| trebati | TRE-ba-ti | should, to need | treba (see below) |
Two of these have a quirk worth flagging on day one: moći and hteti are the only two verbs in the whole language whose "I" form ends in -u rather than the usual -m — mogu, hoću. Every other verb you'll meet, modal or not, takes -m (moram, smem, radim, pijem). File that away and the two odd ones stop feeling odd.
The one rule: da + present (or the infinitive)
This is the whole mechanism, and it's the single most useful thing on the page. After a modal, the second verb goes in one of two shapes:
- da + present tense: Moram da idem — "I have to go." The second verb agrees with the subject, just like a normal present-tense verb.
- the infinitive: Moram ići — same meaning, the dictionary form of the verb, unchanging.
Both are correct. The catch is where you are. In Serbia, da + present is the everyday default — so common that the bare infinitive can sound stiff or bookish. In Croatia it's the mirror image: you'll hear the infinitive and almost never da. Montenegro leans the Serbian way. The good news is that either version is understood the length and breadth of the region, so you never have to choose "correctly" — just lean toward da + present if you're learning with Serbia or Montenegro in mind, and toward the infinitive for Croatia.
| English | Serbia / Montenegro (da + present) | Croatia (infinitive) |
|---|
| I can help. | Mogu da pomognem. | Mogu pomoći. |
| I want to try. | Hoću da probam. | Hoću probati. |
| I have to go. | Moram da idem. | Moram ići. |
The forms, in full
You mostly need the "I" and "you" forms to start talking, but here are the three you'll use constantly, laid out. Notice that moći softens its g to a ž everywhere except the two -u forms.
| moći (can) | morati (must) | hteti (want) |
|---|
| ja | mogu | moram | hoću |
| ti | možeš | moraš | hoćeš |
| on/ona | može | mora | hoće |
| mi | možemo | moramo | hoćemo |
| vi | možete | morate | hoćete |
| oni | mogu | moraju | hoće |
One small bonus you get for free: hteti is the same verb that builds the Serbian future tense. Its shortened forms — ću, ćeš, će — are just hoću, hoćeš, hoće with the front worn off. Learn hoću as "I want" and you've quietly half-learned "I will" too.
The trap: ne moram is not ne smem
English blurs two ideas that Serbian keeps firmly apart, and it's the mistake nearly every learner makes once. In English "you don't have to" and "you mustn't" both start the same way; in Serbian they're different verbs with opposite force:
Ne moram da radim sutra. — I don't have to work tomorrow. (no obligation — but I may)
Ne smem da kasnim. — I mustn't be late. (a prohibition — it's not allowed)
So ne moram removes an obligation, while ne smem forbids something. If you want to tell a child "you mustn't touch that," it's Ne smeš to da diraš — never ne moraš, which would cheerfully give them permission to skip it.
Saying "I don't want to": neću
The negative of hteti is written as a single word — neću, nećeš, neće — and it's one of the first things worth banking, because you'll reach for it constantly to decline politely. Neću, hvala — "I don't want to / no, thanks." Neće da jede — "he won't eat / doesn't want to eat." For a softer, more formal "I'd rather not," people often switch to ne želim (from želeti, to wish) or the very polite conditional ne bih ("I wouldn't").
The tricky one: trebati
Trebati earns its own section because it behaves in two different ways, and mixing them up is the commonest trebati error. Which one you want depends on whether you need a thing or need to do something.
| You need… | Pattern | Example |
|---|
| a thing (a noun) | treba mi + noun | Treba mi voda. — I need water. |
| to do something | treba da + present | Treba da idem. — I should / need to go. |
The surprise in treba mi voda is that it's built back-to-front from English: literally "to-me is-needed water," so the thing you want (voda) is the subject and you are in the dative — meni / mi. Change the thing and the verb agrees with it, not with you: Trebaju mi cipele — "I need shoes" (plural thing, so trebaju). For actions, keep treba impersonal in the third person: Treba da učim (I should study), Treba da idemo (we should go). In careful Serbian you avoid trebam da idem; let treba sit still and let the second verb do the agreeing.
A real exchange, start to finish
Here's how these five verbs actually stack up in a thirty-second conversation between friends making plans:
A: Hoćeš da izađemo večeras? — Do you want to go out tonight?
B: Ne mogu, moram da radim. Možda sutra? — I can't, I have to work. Maybe tomorrow?
A: Važi. Treba li ti nešto? — OK. Do you need anything?
B: Hvala, treba mi samo malo sna. — Thanks, I just need some sleep.
Four lines, and every modal on this page has already earned its keep — want, can, must, need-to and need-a-thing, all doing ordinary work.
Try it (answers below)
Cover the answers and turn each of these into Serbian:
- Say "I have to go."
- Ask a friend "Can you help me?"
- Say "I don't want to, thanks."
- Say "I need money."
- Warn someone "You mustn't be late."
Answers: 1) Moram da idem. 2) Možeš li da mi pomogneš? (or Da li možeš da mi pomogneš?) 3) Neću, hvala. 4) Treba mi novac. 5) Ne smeš da kasniš.
Quick questions
Do I use the infinitive or "da + present" after a modal? Both are correct, but they split by region. In Serbia the everyday choice is da + present: Moram da idem (I have to go). The plain infinitive, Moram ići, is grammatically fine but sounds bookish there. In Croatia it's the opposite — you'll hear only the infinitive. Either version is understood everywhere, so pick the one that matches where you're learning.
What's the difference between "ne moram" and "ne smem"? They're the classic false-friend pair. Ne moram means "I don't have to" — no obligation, but I may if I want. Ne smem means "I mustn't / I'm not allowed" — a prohibition. Ne moram da radim is a world away from Ne smem da kasnim.
How do I say "I need" — trebati or "treba mi"? For a thing, use treba mi + noun: Treba mi voda (I need water). For an action, use treba da + present: Treba da idem (I should/need to go). In standard Serbian "trebam da idem" is avoided; treba stays impersonal.
Are modal verbs the same in Montenegrin and Croatian? The verbs and rules are shared; only the ijekavian spellings differ (htjeti, smjeti) and Croatia prefers the infinitive. Meanings and conjugations don't change. If the vowel patterns are new to you, Montenegrin pronunciation lays them out.
Modal verbs are the fastest jump from naming things to actually doing things with the language — the moment you can say hoću, moram and mogu, you're negotiating, offering and planning rather than just labelling. The way they stick isn't a table; it's saying moram da idem and možeš li da mi pomogneš out loud until the da attaches itself without thought. That's the small, real drilling Gora's fox is built for — and when you're ready to see where these fit in the bigger picture, the Serbian roadmap lays out a sensible order and the Serbian course takes you through it. Search Gora Academy in the App Store or on Google Play, or open it in your browser at app.gora.academy.
Practise the modals out loud — free →