Inflected personal infinitive

In brief

In Brazilian Portuguese, an infinitive can change its ending to show who performs the action. This is useful in phrases such as ‘for us to leave’ or ‘before they arrive’: the infinitive identifies its own subject without turning the phrase into a full clause.

Form

Start with the infinitive: falar → (eu) falar, (você/ele/ela) falar, (nós) falarmos, (vocês/eles/elas) falarem. With você and vocês, use the third-person forms shown; the ending for eu is identical to the plain infinitive.

Usage

• Use it after para to express who needs to do something: para nós chegarmos cedo.
• Use it after antes de or sem when the following action has its own subject; a stated pronoun can make that subject especially clear.

Examples

• Para chegarmos cedo, precisamos sair agora. — For us to arrive early, we need to leave now.
• Antes de vocês saírem, fechem a porta. — Before you leave, close the door.
• É importante eles lerem as instruções antes da prova. — It’s important for them to read the instructions before the exam.

Common mistake

❌ Para nós chegar cedo, precisamos sair agora.

✅ Para nós chegarmos cedo, precisamos sair agora.

When nós is the subject of this infinitive phrase, add -mos: chegarmos. English ‘for us to arrive’ does not change the infinitive, so it is easy to miss the Portuguese ending.

Remember

The personal infinitive has no separate past or future tense; context supplies the time reference.