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The Personal Infinitive: A Crucial Concept Unique to Portuguese Grammar

The personal infinitive is one of the central structures of Portuguese grammar; you can’t really have a conversation without using it. It’s also something of an oddity—it’s not found in other Romance languages such as Spanish and Italian. Practice with a tutor to master the use of the personal infinitive and other aspects of Portuguese grammar.

What Is the Personal Infinitive?

The infinitive form of a verb is the abstract form it takes when not conjugated for the first, second, or third person, or for any specific tense. This is usually the form used for the dictionary definition of a verb. In Portuguese, you can spot infinitives because they end in -er, -ir, or -ar. Normally, when a verb is combined with a personal pronoun, it is conjugated in a manner specific to the type of pronoun and the tense being used. So, the verb ter (to have), when conjugated for the first person present tense, becomes eu tenho (I have).

In Portuguese grammar, however, there are specific instances when a verb is used in combination with a personal pronoun and is not conjugated but retains the infinitive form. This is called the personal infinitive. It is very common, but you can’t do it all the time, so you need to know the rules governing its use.

When Do You Use It?

There are two basic situations when Portuguese grammar permits the use of the personal infinitive: after certain prepositions that express situations that are either hypothetical or yet to occur, and in the subjunctive mood. The subjunctive mood is a grammatical mood in which the speaker expresses an attitude toward a hypothetical situation: for instance, in English, “it is important that we go to the bank today” is an example of a subjunctive.

In a moment, we’ll take a look at how this works in practice. Before that, there’s one rule for using the personal infinitive that we need to examine: the use of personal infinitive suffixes.

Personal Infinitive Suffixes

In some (but not all) cases, when using the personal infinitive, a suffix needs to be added. This depends on what pronoun is being used. If you’re using the first person, the third person singular, or the irregular second-person pronoun você (which uses third-person conjugations), you won’t need to add a suffix. Here’s a list of the pronouns where a suffix is necessary and the suffixes you need to use.

Pronoun: Tu

Suffix: -es

Pronoun: Nós

Suffix: -mos

Pronouns: Eles, elas, vocês

Suffix: -em

Now, we’ll take a look at how to put the personal infinitive into practice in the two different situations described above: after prepositions and in the subjunctive.

After Prepositions

It’s important to note that Portuguese grammar doesn’t allow you to use the personal infinitive after any old preposition. The kind of preposition we’re looking for is one that refers to a state of affairs that has yet to occur or that is in some way hypothetical. Here are some examples, with the personal infinitive underlined in the Portuguese sentence:

After reading this you will know more.

Depois de ler isso, você saberá mais.

For us to get to the station, we should run.

Para chegarmos à estação, devemos correr.

In order for them to know more, they should buy the book.

Para saberem mais, eles devem comprar o livro.

You’ll keep practicing until you make it.

Tu continuarás a praticar* até conseguires.

*This is European Portuguese; in Brazilian Portuguese you’d use the gerund, as in tu continuarás praticando.

In the Subjunctive Mood

Here are some examples of how to use the personal infinitive in the subjunctive mood. Once again, the personal infinitives are underlined in the Portuguese sentences.

It would be good to hire a tutor to help you with this.

É bom você contratar um tutor para ajudá-lo com isso.

It is important that we go to the bank today.

É importante nós irmos ao banco hoje.

It would be hard for them to find.

É difícil eles encontrarem.

It would be good to hire a tutor to help you with this.

É bom tu contratares um tutor para te ajudar com isso.

Just to make it more complicated, Portuguese also has a subjunctive mood in which the personal infinitive is not used! If you explicitly use the word que, meaning “that,” as in é bom que…, you have to conjugate the verb for the subjunctive mood, and you cannot use the personal infinitive.

Support for This and More

The personal infinitive requires practice to master when to use it, and when to use a suffix. The best way of mastering the subject is to learn with a tutor who can help you with all the subtleties, and with all the other complexities of Portuguese grammar.

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