When you perceive something — see it, hear it, feel it — you can perceive it in two fundamentally different ways: you can witness the event itself unfolding before your senses, or you can infer a fact from what you take in. Brazilian Portuguese encodes this difference grammatically in how perception verbs (ver, ouvir, sentir, observar, notar, escutar) take their complements. Direct, sensory perception of an action uses a non-finite complement (gerund, personal infinitive, or bare infinitive); inferred or factual perception uses a que-clause. Getting this right is one of the more elegant pieces of advanced Portuguese, and Brazilians switch among the options fluidly depending on the texture of meaning they want.
English has the same direct/indirect split ("I saw him leave" vs. "I saw that he had left"), but English only offers a bare infinitive or an -ing form for the direct case. Portuguese gives you a third option — the personal infinitive — and the three-way choice carries real meaning.
Direct perception: three non-finite options
When you actually witnessed the action with your senses, the complement is non-finite, and you have three forms to choose from. They are not interchangeable — each frames the perceived action differently.
Gerund — an ongoing scene
The gerund (-ndo) presents the action as in progress at the moment of perception. You caught it mid-flow; you are describing a scene, not its completion.
Vi as crianças brincando no quintal quando cheguei.
I saw the children playing in the yard when I arrived.
Ouvi alguém cantando no apartamento de cima.
I heard someone singing in the apartment upstairs.
Senti o chão tremendo durante alguns segundos.
I felt the ground shaking for a few seconds.
The gerund is the most common choice in everyday Brazilian Portuguese for perceived activity, precisely because so much of what we perceive we catch in mid-action. Vi as crianças brincando paints a picture: there they were, playing.
Personal infinitive — a bounded event
The personal infinitive (brincarem, cantarem, saírem) presents the action as a whole, bounded event — something you witnessed from start to finish, or as a single complete occurrence rather than an ongoing scene.
Vi as crianças brincarem e depois entrarem para jantar.
I saw the children play and then go in for dinner.
Ouvi os vizinhos discutirem a noite inteira.
I heard the neighbors argue the whole night.
Compare Vi as crianças brincando (I caught them in the middle of playing) with Vi as crianças brincarem (I witnessed the playing as a complete event). The personal infinitive also carries the person ending, which makes the subject of the perceived action explicit and is favored in careful or written register (formal/careful speech).
Bare infinitive — colloquial
The bare (impersonal) infinitive — brincar, cantar without a person ending — also occurs, especially in casual speech where the personal ending is dropped. It is the loosest, most colloquial of the three.
Vi as crianças brincar lá fora.
I saw the children playing out there.
A gente ouviu o vizinho gritar de madrugada.
We heard the neighbor shout in the early morning.
In careful writing, with a plural causee you would usually mark the personal infinitive (brincarem); in relaxed speech the bare brincar is common and unremarkable (informal). Both are accepted; the bare form simply signals a more casual register.
Indirect perception: que + finite clause
When you did not witness the action directly but inferred a fact — you noticed a state, drew a conclusion, registered that something was the case — Portuguese switches to a que-clause with a finite verb. This is the perception of a proposition, not of an event.
Vi que ele estava nervoso pelo jeito que mexia nas mãos.
I could see he was nervous from the way he fidgeted with his hands.
Notei que ele tinha mudado bastante desde a última vez.
I noticed he had changed a lot since the last time.
Senti que algo estava errado assim que entrei.
I felt that something was wrong as soon as I came in.
You did not literally see his nervousness as an action — you saw clues and inferred the fact "he was nervous." That inference is what the que-clause encodes. The verb in the que-clause is normally indicative (it reports a fact you concluded): Vi que ele estava nervoso, not the subjunctive.
A four-way comparison
| Complement | Meaning | Example | Register |
|---|---|---|---|
| Gerund (-ndo) | Ongoing scene, caught mid-action | Vi ele saindo | neutral, very common |
| Personal infinitive | Bounded, complete event | Vi ele sair (sg.) / Vi eles saírem | careful / written |
| Bare infinitive | Same as above, looser | Vi eles sair | colloquial |
| que + indicative | Inferred fact / state | Vi que ele tinha saído | neutral |
(Note that with a singular causee the bare and personal infinitive coincide in form — Vi ele sair — so the contrast is most visible in the plural: Vi eles sair vs. Vi eles saírem.)
Why the gerund is so frequent in Brazil
Brazilian Portuguese is famously fond of the gerund, far more than European Portuguese (which often prefers a + infinitive: vi-os a brincar). For perception, this means the gerund is the default Brazilian choice for a witnessed action in progress, and the a + infinitive construction is essentially absent from Brazilian speech (regional: contrast with European Portuguese).
Fiquei observando o sol se pondo atrás dos prédios.
I stood watching the sun setting behind the buildings.
Escutei o bebê chorando no quarto ao lado.
I heard the baby crying in the next room.
This is worth internalizing: if you reach for vi ele a brincar (the European pattern), Brazilians will understand you but immediately hear it as non-Brazilian. Use the gerund.
Common Mistakes
❌ Vi ele a brincar no quintal.
Incorrect for Brazilian Portuguese — 'a + infinitive' is the European pattern; Brazil uses the gerund.
✅ Vi ele brincando no quintal.
I saw him playing in the yard.
❌ Vi que ele saindo do prédio.
Incorrect — after 'que' you need a finite verb, not a gerund.
✅ Vi ele saindo do prédio.
I saw him coming out of the building.
❌ Notei ele estar nervoso. (intended: I noticed he was nervous)
Unnatural — an inferred state takes a 'que'-clause, not a bare infinitive.
✅ Notei que ele estava nervoso.
I noticed he was nervous.
❌ Vi que ele saísse mais cedo.
Incorrect mood — perceived facts take the indicative, not the subjunctive.
✅ Vi que ele saiu mais cedo.
I saw that he left earlier.
❌ Ouvi os vizinhos discutir a noite inteira (in careful writing).
In careful register, a plural causee usually takes the personal infinitive ending.
✅ Ouvi os vizinhos discutirem a noite inteira.
I heard the neighbors argue the whole night.
Key Takeaways
- Direct perception of an action → non-finite complement: gerund (ongoing scene), personal infinitive (bounded event), or bare infinitive (colloquial).
- Inferred or factual perception → que + finite indicative clause: Notei que ele tinha mudado.
- The gerund is the Brazilian default for an action in progress; the European a
- infinitive is not used in Brazil.
- With a plural causee the personal infinitive (discutirem) is the careful choice; the bare discutir is colloquial.
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