Perception Verbs with Infinitive or Gerund | Portuguese (Portugal) Grammar

Portuguese has a small family of verbs of perception — ver (to see), ouvir (to hear), sentir (to feel), notar (to notice), observar (to observe), avistar (to catch sight of) — that all share a distinctive complement pattern: perception verb + object + complement. What sits in the complement slot depends on what kind of perception the speaker is describing. Is the speaker reporting the event they witnessed, or describing an ongoing process caught in the act? European Portuguese encodes that distinction grammatically, and the choice between infinitive and a + infinitive is the single most important thing on this page.

This is also the page where the biggest split between European Portuguese (EP) and Brazilian Portuguese (BP) is most visible. Where EP says vi a Maria a chegar ("I saw Maria arriving"), BP uses the gerund: vi a Maria chegando. The meanings are identical, but the structures are different — and confusing them is the single clearest tell of which variety someone speaks. If you are learning European Portuguese, the a + infinitive pattern is the one to internalise; the gerund sounds Brazilian.

The two complement patterns

Perception verbs in European Portuguese take one of two complement shapes after the object:

Pattern 1: Perception verb + object + infinitive (the event reading)

This pattern reports a complete event that the perceiver witnessed from start to finish. The infinitive is bare — no preposition.

Vi a Maria chegar. — I saw Maria arrive. (I witnessed her arrival as an event.)

Pattern 2: Perception verb + object + a + infinitive (the ongoing-process reading)

This pattern reports the act in progress, caught mid-stream. The infinitive is preceded by the preposition a, producing a progressive-like reading.

Vi a Maria a chegar. — I saw Maria arriving. (I caught her in the act of arriving.)

The semantic contrast is subtle but genuine. Vi a Maria chegar focuses on the arrival as a bounded event — you saw the whole thing. Vi a Maria a chegar zooms in on a moment of the process — you saw her in the middle of approaching, but the event wasn't necessarily complete when you saw it, nor did you necessarily watch it from start to finish.

Vi a Maria chegar.

I saw Maria arrive. (event reading — I witnessed the arrival)

Vi a Maria a chegar.

I saw Maria arriving. (process reading — I saw her in the act)

Ouvi o bebé chorar às três da manhã.

I heard the baby cry at three in the morning. (the event, as a single occurrence)

Ouvi o bebé a chorar no quarto.

I heard the baby crying in the bedroom. (ongoing — I heard it while it was happening)

Sentimos a casa tremer.

We felt the house shake. (event — the shake happened and we felt it)

Sentimos a casa a tremer.

We felt the house shaking. (ongoing — the shaking was happening)

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The infinitive after a perception verb reports a witnessed event. The a + infinitive reports a witnessed process in progress. When in doubt, check the English gloss: if saw X arrive sounds right, use the infinitive; if saw X arriving sounds right, use a + infinitive.

The EP / BP split

The European Portuguese a + infinitive is the exact functional equivalent of Brazilian Portuguese's gerund. They express the same ongoing-process reading, and in every sentence where EP says a + infinitive, BP says -ndo.

European Portuguese	Brazilian Portuguese	English
Vi a Maria a chegar.	Vi a Maria chegando.	I saw Maria arriving.
Ouvi o João a cantar.	Ouvi o João cantando.	I heard João singing.
Senti a terra a tremer.	Senti a terra tremendo.	I felt the ground shaking.
Notei-a a olhar-me.	Notei-a me olhando.	I noticed her looking at me.
Observei-os a trabalhar.	Observei-os trabalhando.	I watched them working.

European Portuguese does have a gerund — it is used after estar in the progressive (estou a fazer vs BP estou fazendo), after andar, ir, vir, and in absolute constructions. But as the complement of a perception verb, the gerund is not the standard European option. A sentence like vi a Maria chegando sounds clearly Brazilian to a Portuguese ear. You will hear it occasionally in Portugal, particularly in media and writing influenced by Brazilian sources, but it is not the native pattern.

When you are writing or speaking in European Portuguese, default to a + infinitive for the ongoing-process reading after a perception verb.

Vi o João a beijar a Ana.

I saw João kissing Ana.

Encontrei a minha filha a estudar para o exame.

I found my daughter studying for the exam.

Ouvi-te a falar sozinho no quarto.

I heard you talking to yourself in the bedroom.

The perception verbs individually

Ver — "to see"

Ver is the most frequent perception verb and the model for the whole pattern. It takes both complement types.

Vi o Pedro atravessar a rua.

I saw Pedro cross the street. (event — the whole crossing)

Vi o Pedro a atravessar a rua.

I saw Pedro crossing the street. (in the middle of crossing)

Viste-me entrar?

Did you see me come in? (event — my entrance)

Viste-me a entrar?

Did you see me coming in? (in the act)

Ouvir — "to hear"

Ouvir behaves identically. The infinitive pattern is especially common with auditory events that are brief and bounded (a cry, a bang, a door slam); the a + infinitive pattern fits longer, sustained sounds.

Ouvi alguém bater à porta.

I heard someone knock at the door. (a discrete knock)

Ouço-os a discutir lá em baixo.

I can hear them arguing downstairs. (sustained)

Ouvi o telefone tocar e atendi.

I heard the phone ring and I answered. (the ringing as an event)

O telefone estava a tocar quando eu cheguei — ouvi-o a tocar do corredor.

The phone was ringing when I arrived — I heard it ringing from the corridor.

Sentir — "to feel"

Sentir refers to physical or emotional perception. The event vs. process distinction applies here too.

Senti o chão vibrar.

I felt the floor vibrate. (bounded event)

Sentia o coração a bater mais depressa.

I could feel my heart beating faster. (ongoing)

Senti uma mão tocar-me no ombro.

I felt a hand touch my shoulder.

Sentia-me a ficar cansada.

I was feeling myself getting tired. (ongoing — gradual)

Notar — "to notice"

Notar emphasises conscious perception — the moment of noticing. It combines more readily with a + infinitive because "noticing" tends to catch things in progress.

Notei-o a olhar para mim.

I noticed him looking at me.

Não tinha notado a Maria a entrar.

I hadn't noticed Maria come in.

Notaste algo estranho a acontecer?

Did you notice anything strange going on?

Observar — "to watch / observe"

Observar describes sustained, deliberate watching. It is heavily biased toward the a + infinitive pattern because observation is by nature an ongoing act.

Observámos os pássaros a fazer o ninho.

We watched the birds making their nest.

Ficou a observar-me a trabalhar.

He sat watching me working.

Avistar, vislumbrar, reparar em

These are the less frequent cousins of the main perception verbs. They follow the same patterns.

Avistei um barco a aproximar-se da costa.

I spotted a boat approaching the coast.

Vislumbrei alguém a passar atrás da cortina.

I glimpsed someone going past behind the curtain.

Reparaste no miúdo a chorar ali ao fundo?

Did you notice the kid crying over there at the back?

Clitic placement with perception verbs

When the object is pronominal, it cliticises to the perception verb — not to the infinitive. This is the same rule that governs causatives: the matrix verb attracts the clitic.

Enclitic (default)

Vi-o sair.

I saw him leave.

Ouvi-as a cantar.

I heard them singing.

Senti-o tremer.

I felt him tremble.

Proclitic (under triggers)

Não o vi sair.

I didn't see him leave.

Nunca a ouvi a cantar.

I never heard her sing.

Quem te viu entrar?

Who saw you come in?

Ainda os ouço a discutir lá em cima.

I can still hear them arguing upstairs.

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The clitic attaches to the perception verb, never to the embedded infinitive. Vi-o sair, not vi sair-o. This is the same principle that governs causatives and most matrix-embedded verb combinations in European Portuguese.

Personal infinitive

When the object of the perception verb is plural (or when there is some reason to mark person explicitly), European Portuguese allows a personal infinitive — a person-marked infinitive form whose ending agrees with the perceived subject. This is especially characteristic of formal and written registers.

Vi os miúdos saírem da escola.

I saw the kids leave school. (personal infinitive — 3pl -em ending)

Ouvimos os vizinhos discutirem a noite toda.

We heard the neighbours arguing all night. (personal infinitive — 3pl -em)

Vi-vos chegarem de mãos dadas.

I saw you arrive holding hands. (personal infinitive — 2pl -des/-em)

The bare infinitive (vi os miúdos sair) is also fully grammatical and perhaps more common in colloquial speech. The personal infinitive adds clarity about the subject and is especially useful when the sentence is long or ambiguous.

The personal infinitive is not used with the a + infinitive pattern. Vi os miúdos a saírem is marginal — the expected form is vi os miúdos a sair, which stays in the singular regardless of number. This is an important exception: the a + infinitive construction treats the infinitive as a gerund-like element that does not take person marking.

Word order and embedded objects

When the infinitive has its own object, the word order can get dense. The natural order in European Portuguese is:

perception verb + object (perceived subject) + infinitive + object (of infinitive)

Vi o João beijar a Ana.

I saw João kiss Ana. (event)

Vi o João a beijar a Ana.

I saw João kissing Ana. (ongoing)

Ouvi a professora elogiar os alunos.

I heard the teacher praise the students.

If the object of the infinitive is pronominal, it cliticises to the infinitive itself (not to the perception verb):

Vi o João beijá-la.

I saw João kiss her. (la cliticises to beijar)

Ouvi a professora elogiá-los.

I heard the teacher praise them.

This is a subtle point: the object of the perception verb cliticises to the perception verb, but the object of the embedded infinitive cliticises to the infinitive. Both can appear in the same sentence: vi-o beijá-la — I saw him kiss her.

Vi-o beijá-la à porta do café.

I saw him kiss her at the café door.

Perception with a que-clause

Perception verbs can also take a full que-clause as complement — especially when the perception is of a fact rather than a directly witnessed act. In this case the complement is an indicative clause.

Vi que ele estava cansado.

I saw that he was tired. (perception of a state, not of an action)

Ouvi dizer que ela se mudou.

I heard that she moved. (reported information)

Notei que faltavam alguns livros.

I noticed that some books were missing.

This que-complement is not a witnessed act; it is a conclusion or report. Vi que ele estava cansado means "I could tell he was tired" — not that you actually watched his state of tiredness happen. The witnessed-event readings use the infinitive or a + infinitive instead.

Common Mistakes

❌ Vi a Maria chegando.

Incorrect in European Portuguese — the gerund is the Brazilian pattern; EP uses a + infinitive.

✅ Vi a Maria a chegar.

I saw Maria arriving.

❌ Ouvi o bebé de chorar.

Incorrect — perception verbs take a (not de) with infinitive for ongoing actions.

✅ Ouvi o bebé a chorar.

I heard the baby crying.

❌ Vi sair-o da sala.

Incorrect — the pronoun cliticises to the perception verb, not the infinitive.

✅ Vi-o sair da sala.

I saw him leave the room.

❌ Não vi-o entrar.

Incorrect — negation is a proclitic trigger, so the clitic must move forward: não o vi entrar.

✅ Não o vi entrar.

I didn't see him come in.

❌ Vi os miúdos a saírem da escola.

Marginal — with a + infinitive, use the impersonal infinitive (no -em ending).

✅ Vi os miúdos a sair da escola.

I saw the kids leaving school.

❌ Vi que a Maria a chegar.

Incorrect — que + indicative is for perceived facts; for witnessed acts use the infinitive without que.