Infinitivo Pessoal x Impessoal

Level 4

Portuguese is unique for having a Personal Infinitive (inflected) alongside the standard Impersonal Infinitive (dictionary form). Use the personal version when the subject of the infinitive is different from the main subject or needs clarification.

How It Works

The distinction between these two forms is a hallmark of Portuguese.

1. The Impersonal Infinitive (Infinitivo Impessoal)
This is the basic form ending in -ar, -er, or -ir. It is used when:

  • The action is abstract or general: Viver é aprender. (Living is learning.)
  • It follows a modal verb like poder, ter que, or dever.
  • The subject is the same as the main verb and no emphasis is needed.

2. The Personal Infinitive (Infinitivo Pessoal)
This form is created by adding endings to the full infinitive:

  • Eu: (none) - falar
  • Tu: -es - falares
  • Ele/Ela/Você: (none) - falar
  • Nós: -mos - falarmos
  • Vós: -des - falardes
  • Eles/Elas/Vocês: -em - falarem

When to use the Personal Infinitive:

  • Different Subjects: When the person doing the infinitive action is not the person doing the main verb action. Example: Eu trouxe comida para eles comerem.
  • Clarity: To identify the subject when it might be ambiguous.
  • After Prepositions: It is very common after para, sem, depois de, and ao.

Note on Irregular Verbs: Unlike the future subjunctive, the personal infinitive is always regular. You take the dictionary form (e.g., ser, ter, ir) and add the endings (sermos, termos, irmos).

Examples (5)

  1. Eles saíram sem dizer nada.

    They left without saying anything.

    Word by Word: They left without to-say nothing.

    Uses the impersonal infinitive 'dizer' because the subject (they) is the same for both verbs.

  2. Eu comprei os livros para vocês lerem.

    I bought the books for you all to read.

    Word by Word: I bought the books for you-all to-read(plural).

    Uses the personal infinitive 'lerem' because the subject of the reading (vocês) is different from the subject of the buying (eu).

  3. É importante estudarmos todos os dias.

    It is important for us to study every day.

    Word by Word: Is important to-study(we) all the days.

    The ending '-mos' identifies 'us' as the subject, making the sentence clear without needing the pronoun 'nós'.

  4. Para seres feliz, precisas de relaxar.

    In order for you to be happy, you need to relax.

    Word by Word: For to-be(you-informal) happy, you-need of to-relax.

    Common in European Portuguese; 'seres' is the personal infinitive for 'tu', while 'relaxar' remains impersonal after the main verb.

  5. Depois de terminarem o trabalho, podem sair.

    After they finish the work, they can leave.

    Word by Word: After of to-finish(they) the work, they-can to-leave.

    'Terminarem' is personal to clarify who is finishing, while 'sair' is impersonal because it follows the modal 'podem'.

Common Mistakes

  • Inflecting the infinitive after a modal verb (like 'poder' or 'dever').

    Eles podem saírem agora.
    Eles podem sair agora.

    When an infinitive follows a conjugated auxiliary/modal verb, it must remain in the impersonal (dictionary) form.

  • Confusing the personal infinitive with the future subjunctive for irregular verbs.

    Para nós tivermos tempo...
    Para nós termos tempo...

    The personal infinitive uses the dictionary stem (ter -> termos). 'Tivermos' is the future subjunctive stem.

  • Using the impersonal form when the subject is different and explicit.

    Fiz isso para eles saber.
    Fiz isso para eles saberem.

    If the subject is explicitly 'eles' and it differs from the main subject, the infinitive should be inflected for clarity and correctness.

How It Connects

Tap a pattern to see what it builds on and what it leads to.

Infinitivo Pessoal x ImpessoalLevel 4

Learn This First

To understand the contrast between the personal and impersonal infinitive, a learner needs to be familiar with the conjugation of the personal infinitive and the syntactic rule that dictates its use: the presence of a distinct subject from the main clause.

Learn Next

Patterns that build on this one.