The personal infinitive — infinitivo pessoal, also called the infinitivo flexionado (inflected infinitive) — is the feature that makes Portuguese stand out from every other major Romance language. It is an infinitive that carries person and number endings, so that a clause built on an infinitive can have its own subject. The idea is so foreign to English that we have no name for it: the closest we get is "for us to leave," and even that doesn't mark the verb. In Portuguese, the verb itself tells you who the subject is. If you want to sound like an educated Brazilian rather than a textbook, this is non-negotiable.
The forms at a glance
The personal infinitive is built on the plain infinitive plus a small set of endings. The full mechanics are on Forming the Personal Infinitive; here is the shape:
| Subject | falar | comer | partir |
|---|---|---|---|
| eu | falar | comer | partir |
| tu (regional) | falares | comeres | partires |
| você / ele / ela | falar | comer | partir |
| nós | falarmos | comermos | partirmos |
| vocês / eles / elas | falarem | comerem | partirem |
Notice the crucial point: the eu and você/ele/ela forms are identical to the plain infinitive. In Brazilian speech, where tu is largely replaced by você, the personal infinitive only visibly differs from the regular one in the nós form (-mos) and the vocês/eles form (-em). Those two endings are the entire workload.
What it does: gives an infinitive its own subject
The whole purpose is to let an infinitive clause have a subject that's different from — or explicitly stated alongside — the main verb's subject. Watch how the verb inflects to match:
É importante para nós sairmos cedo.
It's important for us to leave early.
É importante para vocês saírem cedo.
It's important for you all to leave early.
The infinitive sair becomes sairmos for "we" and saírem for "you all." Note the accent on saírem — the í is stressed and written with an acute. The endings carry the subject information that English has to spell out with "for us / for you."
Use 1: After prepositions, with a stated subject
This is the most common use. When a prepositional phrase (with para, antes de, depois de, sem, até) introduces an action with its own subject, the infinitive inflects.
O professor repetiu a explicação para todos entenderem.
The teacher repeated the explanation so that everyone would understand.
Antes de eles chegarem, eu já tinha arrumado a casa.
Before they arrived, I had already tidied the house.
Saímos sem os vizinhos perceberem.
We left without the neighbors noticing.
The deep details and the full list of triggering prepositions are on The Personal Infinitive with Prepositions.
Use 2: In adverbial clauses with an overt subject
When you'd otherwise need a heavy subjunctive clause, the personal infinitive offers a lighter alternative — especially after para (in order that) and time expressions.
Falei devagar para os alunos copiarem tudo.
I spoke slowly so the students could copy everything.
No caso de vocês precisarem de ajuda, é só ligar.
In case you all need help, just call.
Use 3: To avoid an awkward subjunctive (formal/written)
In careful writing and formal speech, the personal infinitive often replaces a que + subjunctive clause, producing a cleaner sentence. Both are correct; the infinitive is tidier.
É melhor vocês esperarem aqui.
It's better for you all to wait here. (instead of 'É melhor que vocês esperem aqui')
Convém revermos o contrato antes de assinar.
It's advisable that we review the contract before signing. (formal)
The verb convém (it's advisable) and the construction with rever belong to a careful register — you'd meet this in a contract or a news article rather than in a casual chat. The full treatment of this trade-off is on Replacing the Subjunctive.
Why no other Romance language has this productively
Latin had an infinitive but no inflected one; the personal infinitive is a Portuguese (and Galician) innovation, developed over the medieval period and never lost. Spanish, French, Italian, and Romanian all express these ideas with full subordinate clauses and a subjunctive. Where Portuguese says para chegarmos cedo, Spanish must say para que lleguemos temprano — a complete clause with a conjunction and a subjunctive verb.
When you do NOT use it
The personal infinitive is for clauses with their own subject. If the subject is the same as the main verb's, or there's no specific subject at all, use the plain (impersonal) infinitive instead.
Quero sair cedo.
I want to leave early. (one subject — plain infinitive, no inflection)
É importante chegar cedo.
It's important to arrive early. (general, no specific subject — plain infinitive)
Compare the second one with the inflected version: É importante chegarmos cedo (it's important that we arrive early). The inflection appears precisely because a specific subject ("we") enters the picture. The full decision logic is at Personal vs Impersonal Infinitive.
Common Mistakes
These are the classic transfer errors — English has no inflected infinitive, so learners either forget to inflect or inflect when they shouldn't.
❌ É importante para nós chegar cedo.
Incorrect — with the explicit subject 'nós', the infinitive must inflect.
✅ É importante para nós chegarmos cedo.
It's important for us to arrive early.
❌ Antes de vocês saírem... não, antes de vocês sair.
Incorrect — with 'vocês' the infinitive takes the '-em' ending: 'saírem'.
✅ Antes de vocês saírem, fechem as janelas.
Before you all leave, close the windows.
❌ Eu quero sairmos cedo.
Incorrect — there's only one subject (eu); don't inflect. Use the plain infinitive.
✅ Eu quero sair cedo.
I want to leave early.
❌ O professor falou alto para entendermos todos.
Word-order/agreement error — should be 'para todos entenderem' (subject 'todos' → '-em' form).
✅ O professor falou alto para todos entenderem.
The teacher spoke loudly so everyone would understand.
Key Takeaways
- The personal infinitive lets an infinitive clause have its own subject, marked on the verb itself.
- It visibly differs from the plain infinitive only in the nós (-mos) and vocês/eles (-em) forms in Brazilian usage.
- Use it after prepositions and conjunctions when the clause has a separate, stated subject; use it in writing to avoid a clunky subjunctive.
- Use the plain infinitive when the subject is the same as the main verb or there's no specific subject.
- It's unique to Portuguese (and Galician) among the major Romance languages — a Spanish-style direct translation will over-use the subjunctive.
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Start learning Portuguese→Related Topics
- Forming the Personal InfinitiveB1 — How to build the personal infinitive — the infinitive plus uniform person endings — and why even irregular verbs are perfectly regular here.
- Personal Infinitive after PrepositionsB1 — How and when to inflect the infinitive after prepositions like para, sem, antes de, and em vez de when the clause has its own subject.
- Personal Infinitive Replacing Subjunctive ClausesB2 — How Brazilian Portuguese uses the personal infinitive as a more concise, modern-sounding alternative to que + subjunctive clauses.
- The Infinitive in BR PortugueseA2 — Brazilian Portuguese has two infinitives — the regular (impersonal) one and a unique personal infinitive that carries person endings.
- Personal vs Impersonal InfinitiveB1 — How to decide whether to leave the infinitive bare or inflect it for person — the rule turns on whether the infinitive has its own, distinct subject.