Modal verb + infinitive
With pouvoir (can, may), vouloir (to want) and devoir (must, to have to) you say what is possible, what you want and what has to happen. Only the modal is conjugated. The second verb stays in the infinitive, with no word like English to in between.
Je peux parler français.
I can speak French.
Je dois partir.
I have to leave.
Je ne peux pas venir.
I can't come.
The present-tense forms
pouvoir, vouloir, devoir
| Person | pouvoir (can) | vouloir (want) | devoir (must) |
|---|---|---|---|
| je | peux | veux | dois |
| tu | peux | veux | dois |
| il / elle / on | peut | veut | doit |
| nous | pouvons | voulons | devons |
| vous | pouvez | voulez | devez |
| ils / elles | peuvent | veulent | doivent |
Present tense
In all three verbs the je and tu forms are identical. For nous and vous the stem of the infinitive comes back: pouv-ons, voul-ons, dev-ons.
What are they used for?
pouvoir: possibility, permission, requests
Je peux venir demain.
I can come tomorrow.
On peut entrer ?
May we come in?
Tu peux m'aider ?
Can you help me?
vouloir: wishes
Je veux is as blunt as English "I want". For requests and orders, use je voudrais (I would like), a fixed phrase.
Je veux apprendre le français.
I want to learn French.
Tu veux un café ?
Do you want a coffee?
Je voudrais réserver une table.
I would like to book a table.
devoir: obligation
Nous devons travailler.
We have to work.
Tu dois faire attention.
You must be careful.
savoir: learned skills
English "can" for a skill you have learned is savoir (je sais, elle sait), not pouvoir. Use pouvoir when circumstances allow something.
Je sais nager.
I can swim.
Elle sait conduire.
She can drive.
