personal infinitive in portuguese

Impersonal vs Personal Infinitive

This learning note will cover the personal infinitive in Portuguese and how it is distinguished from the impersonal infinitive.
First let’s review what we mean by infinitive. The infinitivo infinitive is one of the three formas nominais nominal forms verbs can have. These nominal forms do not express the verb tense, mode, and person by themselves, as they are dependent on the context in which they appear. The infinitive expresses the idea of an action and it could be thought of as the base form of the verb.
There are two types of infinitives: impessoal impersonal and pessoal personal. We’ll dive into each type below and explain the differences.

Impersonal Infinitive

The infinitivo impessoal impersonal infinitive is invariable, meaning it appears in its full form (without any conjugation) as it doesn’t have a subject.
É obrigatório lavar as mãos. Washing hands is mandatory.
The example above is not referring to anyone specific, just to the general idea of “washing”.
However, the infinitive can also appear as the subject of a sentence itself.
Errar é humano. To err is human.
Amar é viver. To love is to live.
Again, the verbs refer to the general idea of the action, rather than to a specific person doing the action.

Personal Infinitive

The infinitivo pessoal personal infinitive differs because there is a known subject. It is formed by adding the following endings to the impersonal infinitive:

  • -es (tu),
  • -mos (nós),
  • -des (vós), or
  • -em (eles, elas, vocês)

(Because the 2nd person plural vós is rarely used nowadays, we’ll focus our attention on the other three.)
The following table shows how the personal infinitive is conjugated with three different verbs.

ir (to go) comer (to eat) falar (to speak)
eu ir comer falar
tu ires comeres falares
ele / ela / você ir comer falar
nós irmos comermos falarmos
eles / elas / vocês irem comerem falarem

As you can see, the 1st and 3rd person singular conjugations are the same as the impersonal infinitive, which can sometimes be a little confusing. We’ll now look into how each one is used.

When do I use the impersonal vs. the personal infinitive in Portuguese?

Knowing which type of infinitive to use may not be as straightforward as you might think. Linguists can’t seem to reach a consensus on the rules that regulate the use of the infinitive, so instead we will show a list of the most common tendencies for each type.

Impersonal

We use the impersonal infinitive:

  • When there’s no reference to a subject. (Or when the infinitive verb is the subject itself, as in some of the earlier examples).
É bom dançar. It's good to dance.
  • When the verb acts as a complement to a noun, verb, or adjective that needs a preposition:

Foram decisões fáceis de tomar. They were easy decisions to make.
Adjectives like fácil easy, possível possible, capaz capable, bom good, raro rare, among others, which are followed by the preposition de of, will also be followed by a verb in the impersonal infinitive.
The same goes for verbs like estar to be - temporary, andar to walk, ir to go, ficar to stay, and others, followed by the preposition a to.
Other prepositions that are often required by an adjective or verb include para for, to, por for, by, and que than, that.
Estou a fazer o almoço. I'm making lunch.
Vou ter que sair. I'm going to have to leave.

  • In locuções verbais phrasal verbs:

Queres comer em casa? You want to eat at home?
Fomos visitar Coimbra. We went to visit Coimbra.

  • When it depends on causative verb (express that an action causes a change in something else) or stative verb (express a state of being rather than an action), either immediately following them or separated by a pronoun:

Mandem sair as pessoas da sala. Tell the people to leave the room.
Ela viu-o passar na rua. She saw him walking on the street.

Personal

We use the personal infinitive in Portuguese:

  • When the subject is clearly known and expressed:

Acho melhor tu ires com eles às compras. I think it's better for you to go shopping with them.
É bom eles dançarem. It's good for them to dance.
Notice that this last example is similar to the one used above (É bom dançar), but because we added the subject eles theymasc., we had to switch to the personal infinitive and conjugate the verb by adding -em.

  • When the subject is made known by the verb itself:

É melhor (vocês) irem para casa. It's better for you to go home.
É obrigatório (tu) lavares as mãos. It's mandatory for you to wash your hands.
Unlike the previous example (É obrigatório lavar as mãos), which was not directed at any particular person, in this example we are referring to “you”, so we used the personal infinitive and conjugated the verb by adding -es.

When in doubt…

The decision of whether to use the impersonal or personal infinitive can get complicated, but the simplest way to start thinking about it is this: in general, if the focus is more on a particular subject doing the action, use the pessoal personal, and if the focus is more on the general action itself, use the impessoal impersonal

Comments:

  • this is very helpful, I’ve just started Portuguese and I actually do enjoy studying grammar when it’s necessary.

  • I think the word is ‘challenging’, in other words ‘difficult’, I found this very hard to get my head around (and I thought Clitic Pronouns were difficult!)
    Pat

  • I’ve studied these verb infinitives before and I think that the explanation of personal infinitives is particularly good.

    For impersonal infinitives it helps if you have studied French or Spanish, where the infinitive is also used instead of the present participle.

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