If you have ever studied Spanish, French, or Italian, you know the specific kind of headache that comes with complex sentence structures. You want to say something simple like, “It is important for us to imply the rules”, but you hit a wall. In most Romance languages, as soon as the subject of the second verb is different from the first, you are forced into a grammatical gymnastics routine involving the subjunctive mood, relative clauses, and awkward conjunctions.
But Portuguese is different.
Portuguese hides a linguistic “superpower” that allows speakers to bypass these clumsy structures entirely. It is a feature so rare that, among major European languages, it is unique to Portuguese and its close sibling, Galician. It is called the Personal Infinitive (Infinitivo Pessoal).
For learners, this grammar point often looks intimidating at first glance. Conjugating an infinitive? Isn’t the definition of an infinitive that it isn’t conjugated? Once you get past the paradox, however, you will realize that the Personal Infinitive is actually a cheat code—a tool that lets you streamline sentences, avoid the subjunctive, and speak with a precision that other Romance languages can only dream of.
The Problem with Standard Infinitives
To appreciate the solution, we must first look at the problem. In English, we have a very flexible way of connecting subjects to infinitives using the preposition “for.”
- “It is difficult for me to understand.”
- “It is necessary for them to leave.”
In Spanish or French, you cannot translate these sentences word-for-word. The infinitive in those languages is impersonal; it cannot carry a subject. If you want to specify who is doing the action, you must create a subordinate clause.
Spanish: “Es necesario que (ellos) salgan.” (It is necessary that they leave [subjunctive]).
You forced a “que” in there, and you had to switch to the subjunctive mood. It works, but it’s rigid. Portuguese, however, looks at the English structure and says, “I can do that.”
Portuguese: “É necessário eles saírem.”
No “que.” No clause separation. Just the subject and a flexible, conjugated infinitive. It is elegant, efficient, and distinctively Portuguese.
What is the Personal Infinitive?
In linguistics, an infinitive is typically the “base” form of a verb (e.g., falar, comer, partir). It usually has no tense, no mood, and importantly, no person or number. It implies the action in the abstract.
The Portuguese Personal Infinitive breaks this rule by adding endings to the infinitive to indicate who is performing the action. It allows the speaker to clarify the subject within a non-finite clause.
How to Form It
The good news for learners is that the Personal Infinitive is arguably the easiest tense to learn in the entire language. For regular verbs (and irregular verbs), it creates the conjugation by adding suffixes to the standard impersonal infinitive.
Let’s look at the verb Falar (to speak):
- Eu (I): falar (no change)
- Tu (You): falares
- Ele/Ela/Você (He/She/You): falar (no change)
- Nós (We): falarmos
- Eles/Elas/Vocês (They/You all): falarem
The endings are consistent across almost all verbs: -es, -mos, -em. If you can remember the infinitive, you can form the personal infinitive.
The Superpower in Action: Usage Scenarios
So, you have memorized the endings. How do you use this weapon to conquer complex sentences? Here are the three main scenarios where the Personal Infinitive outshines standard grammar.
1. Clarifying the Subject
The most common use is simply avoiding ambiguity. If you use a standard infinitive after a preposition, it isn’t always clear who you are talking about.
Consider the phrase: “Ao chegar…” (Upon arriving…).
If you say this, who arrived? Without context, we don’t know. But with the Personal Infinitive, we can be specific without starting a new sentence.
- “Ao chegares, avisa-me.” (Upon you arriving, let me know.)
- “Ao chegarmos, vamos comer.” (Upon us arriving, we will eat.)
2. The “Subjunctive Killer”
This is the feature that makes learners fall in love with Portuguese grammar. Romance languages are notorious for the Subjunctive Mood—a verb form used to express doubt, possibility, or emotion. It requires memorizing entirely new conjugation tables and complex trigger rules.
While you cannot avoid the subjunctive entirely in Portuguese, the Personal Infinitive offers a grammatically correct “loophole” in many situations. When the subject of the main verb is different from the second verb, you can often choose between a complicated subjunctive clause or a simple personal infinitive structure.
Example: “It is a pity that they don’t study.”
Option A (Subjunctive): “É pena que eles não estudem.”
Option B (Personal Infinitive): “É pena eles não estudarem.”
Both are correct. But Option B feels more direct and mimics the logic of English (“It’s a pity for them not to study”). By mastering this, you can navigate around tricky subjunctive conjugations while maintaining perfect fluency.
3. After Prepositions (Por and Para)
Prepositions are the natural habitat of the Personal Infinitive. This is extremely useful when giving reasons (por) or expressing purpose (para).
Using Para (In order to/For):
If you lend a book to your friends for a specific purpose, you use the personal infinitive because the subject changes from “I” (who lent) to “They” (who will read).
“Emprestei o livro para eles lerem.”
(I lent the book for them to read.)
Using Por (Because of/By):
This creates causal links elegantly.
“Eles foram castigados por não fazerem a cama.”
(They were punished for not making the bed.)
In Italian or Spanish, “for not making” would likely default to a generic infinitive, losing the emphasis that they specifically failed to do it, or requiring a clunky “because they didn’t make…” clause.
A Note for the Linguistic Nerds
Why does Portuguese have this feature while its cousins do not? It is a subject of debate among historical linguists, but generally, it is believed to have developed in the western Iberian Peninsula during the transition from Vulgar Latin to Galician-Portuguese.
Some theories suggest it evolved from the Latin imperfect subjunctive, while others suggest it was an innovation to mimic the flexibility of Celtic constructures or even Arabic influences present in the region. Regardless of its origin, it survived in Portuguese and Galician but was lost or never developed in Castilian (Spanish), Catalan, or French.
It is worth noting that for regular verbs, the Personal Infinitive looks identical to the Future Subjunctive verb forms. While they look the same, they function differently. The Future Subjunctive is used for contingent future events (“Se eu for…” – If I go), while the Personal Infinitive functions as a noun or after prepositions. Context is key!
Conclusion: Embrace the Cheat Code
For language learners, the Personal Infinitive represents a rare instance where grammar actually makes life easier rather than harder. It bridges the gap between the English style of “subject + to verb” constructions and Romance syntax.
Don’t be afraid to use it. If you find yourself about to construct a messy sentence involving “que” and a verb tense you can’t quite remember, pause. Ask yourself if you can simply use a preposition and the Personal Infinitive. More often than not, the answer is yes. It isn’t just a grammar rule; it is Portuguese’s way of letting you express complex thoughts with elegant simplicity.