In short

Three verbs - potere (can), dovere (must), volere (want) - let you say almost anything you cannot yet say with one verb. They are irregular, they are followed by a bare infinitive with no preposition, and only the modal is conjugated: Devo partire, Posso entrare?, Voglio dormire. Learn vorrei (“I’d like”) as a word, not as grammar - it is the politest thing you can say at A1.

The rule

A modal verb does not stand on its own meaning: it modifies a second verb. Italian builds this with two verbs in a row, and the division of labour is strict.

• Step 1 - Conjugate the modal, and only the modal. The modal agrees with the subject; the second verb never does. Io devo studiare, tu devi studiare, loro devono studiare - studiare never moves.
• Step 2 - Put the second verb in the infinitive. That is the dictionary form: -are, -ere, -ire. Not the present, not anything else. Posso parlo is impossible.
• Step 3 - Put nothing between them. No preposition, no di, no a, no che. English says “I have to go” and learners import that to as di. Italian says Devo andare and nothing else. (Some non-modal verbs do take a preposition before the infinitive - that is step 37, and it is exactly why these three are special.)
• Step 4 - Pick the right one for the meaning. potere = it is possible or allowed; dovere = it is required; volere = I want it. If the meaning is “I have learned how to do this”, you need sapere, not potere - see below.

The meaning range

potere covers three English words at once - can, may, might - because it means “nothing is stopping this”. Posso venire can be I’m free to come, I’m allowed to come, or, with things, it’s possible: Può piovere - It may rain.

dovere is obligation from outside: a rule, a timetable, a boss, a need. Devo lavorare is I have to work - not I’d like to. It is stronger than English should; the softened version (dovrei) is the conditional, which comes at step 36.

volere is plain will. It is also the one modal that happily takes a noun instead of an infinitive: Voglio un caffè - I want a coffee.

potere vs sapere - the trap

English “can” hides two different ideas, and Italian splits them.

• sapere + infinitive = to know how to, to have the skill. So nuotare - I can swim (I learned; I am a swimmer).
• potere + infinitive = to be free, able or allowed right now. Oggi non posso nuotare - Today I can’t swim (the pool is closed, my leg hurts).

A person who says Non posso nuotare is saying something is in the way today. A person who never learned says Non so nuotare.

vorrei - learn the word, skip the grammar

Voglio un caffè is grammatically perfect and sounds like a demand. In a shop, a bar or any request to a stranger, Italians replace it with vorrei - I’d like. Vorrei un caffè, per favore. For now treat vorrei as a fixed polite formula that behaves exactly like a modal: Vorrei parlare con Marco. (It is really the conditional of volere; you will take it apart at step 36.)

Forms & patterns

The three modals in the present. All three are irregular. Only voi stays fully regular (potete, dovete, volete); noi takes an irregular stem too (possiamo, dobbiamo, vogliamo - not potiamo/doviamo/voliamo), alongside the four “boot” cells:

The pattern to build the sentence - three slots, in this order:

What each modal actually means:

“Can” in English -> two verbs in Italian:

Examples

Common mistakes

• Devo di andare / Voglio di mangiare -> Devo andare / Voglio mangiare - the English “to” of “I have to go” is not translated. After a modal the infinitive is bare: nothing goes in between.
• Posso parlo italiano -> Posso parlare italiano - only the modal is conjugated. The second verb stays in the dictionary form, whatever the subject is.
• Non posso nuotare (meaning “I never learned”) -> Non so nuotare - a learned skill is sapere. potere would mean something is stopping you today.
• Lui puo venire -> Lui può venire - può carries a grave accent. Without it the word is misspelled; the accent is part of the form, not decoration.
• Voglio un caffè (to a waiter) -> Vorrei un caffè - grammatical, but it lands as an order. vorrei is the polite default with anyone you do not know.

Tips

• volere only looks like a -go verb. voglio … vogliono resembles the g bookend of vengo … vengono from step 9, but its sound is -gli-, not a hard g, and vogliamo keeps it too - it shows up at io, noi and loro, and only vuoi, vuole and volete drop it.
• Two verbs, one subject, no glue. If you remember one thing: modal + infinitive, nothing in the middle. Say Devo andare - Posso andare - Voglio andare out loud as a chain; the shape is identical every time.
• posso / puoi / può is a boot. The o of potere and volere breaks into uo at tu and lui/lei only - puoi, può, vuoi, vuole. Everywhere else it stays a plain o: stressed but shut in by a double consonant at io and loro (posso, possono, voglio, vogliono), and unstressed at noi and voi (possiamo, potete). The boot shape itself is the one you met in uscire -> esco / usciamo.
• vorrei is the magic word. One form, endlessly useful: Vorrei un caffè, Vorrei prenotare, Vorrei sapere. You can survive a whole trip on it before you ever study the conditional.
• You will meet debbo for devo in older books. It is a genuine alternative form, but you never need to produce it - devo is what everyone says.