Indefinite Pronouns: Alguém, Ninguém, Tudo, Nada | Portuguese (Brazil) Grammar

Indefinite pronouns let you talk about people and things without naming them: someone, no one, everything, nothing. This page covers the core invariable ones — words that never change shape — plus the single most important rule they trigger in Brazilian Portuguese: double negation. We will also untangle the pair that trips up nearly every learner, tudo versus todo.

The four core invariables

These four words are the backbone. They never agree in gender or number — they have exactly one form each — which makes them wonderfully easy once you know them.

Portuguese	English	Refers to
alguém	someone, somebody, anyone	people (positive)
ninguém	no one, nobody	people (negative)
tudo	everything	things (positive)
nada	nothing, anything	things (negative)

Mind the accents: alguém and ninguém carry an acute accent on the final é (the stress falls there). Forgetting it is a spelling error, not a typo — alguem is simply wrong.

Alguém bateu na porta.

Someone knocked on the door.

Tudo vai dar certo, relaxa.

Everything's going to work out, relax.

Ninguém me avisou da reunião.

Nobody told me about the meeting.

Não quero nada, obrigado.

I don't want anything, thanks.

Notice how alguém/ninguém pair up (someone / no one for people) and tudo/nada pair up (everything / nothing for things). Keeping the pairs straight by what they refer to — people vs. things — is the fastest way to stop confusing them.

The double-negation rule

Here is the feature that feels wrong to English speakers and is non-negotiable in Portuguese. When a negative indefinite like ninguém or nada comes after the verb, Portuguese also requires the word não before the verb. The sentence carries two negative words, and they reinforce — they do not cancel.

Não vi ninguém na festa.

I didn't see anyone at the party. (literally 'I didn't see no one')

Não tem nada na geladeira.

There's nothing in the fridge. (literally 'there isn't nothing')

Ela não falou nada o dia inteiro.

She didn't say anything all day.

In English, "I didn't see nobody" is considered a mistake — the two negatives are supposed to cancel into a positive. Portuguese works the opposite way: the second negative agrees with and strengthens the first. This is called negative concord, and it is the standard, correct grammar — not slang.

There is one escape from the double negative: if the negative word comes before the verb (as the subject), you drop the não, because the negation is already sitting in front of the verb.

Ninguém me avisou.

Nobody warned me. (negative word before verb — NO 'não')

Nada aconteceu.

Nothing happened. (no 'não' needed)

💡

The rule is positional. Negative word AFTER the verb → you must add não (Não vi ninguém). Negative word BEFORE the verb → no não (Ninguém veio). Same meaning, just two ways to arrange it.

Algo — the formal "something"

Alongside the four core words there is algo ("something"), the thing-counterpart of alguém. In Brazil, algo is noticeably more formal or written than spoken. In everyday speech, Brazilians usually say alguma coisa ("some thing") instead.

Preciso te dizer algo importante.

I need to tell you something important. (slightly formal)

Quer comer alguma coisa?

Do you want to eat something? (everyday, informal — the default in speech)

💡

For "something," prefer alguma coisa in conversation; save algo for writing or a more formal tone. Both are correct — they differ in register, not meaning.

Tudo vs. todo — the contrast that matters most

This is the classic trap. Both relate to "all," but they are different parts of speech and behave differently.

Tudo is an invariable pronoun meaning "everything" — all the things, taken as a whole, with no noun attached. It never changes form and never describes a noun.

Todo / toda / todos / todas is a determiner/adjective meaning "every" or "all," and it agrees in gender and number with a noun it accompanies.

Word	Meaning	Agrees?	Takes a noun?
tudo	everything	No — one form	No — stands alone
todo / toda / todos / todas	every / all (the)	Yes	Yes

Eu comi tudo.

I ate everything. (tudo = the whole lot, no noun)

Eu comi todo o bolo.

I ate the whole cake. (todo + masculine noun 'bolo')

Todas as crianças dormiram.

All the children slept. (todas agrees with feminine plural 'crianças')

Obrigado por tudo.

Thanks for everything. (fixed, extremely common phrase)

The test is simple: if you can replace the English with "everything" and there is no following noun, use tudo. If the English is "every / all the _" with a noun, use todo/toda/todos/todas and make it agree.

💡

Tudo stands alone and never changes (Tudo bem? = "Everything okay?"). Todo leans on a noun and must agree with it (todo dia, toda hora, todos os dias). If there's a noun right after, you want the todo family, not tudo.

Cada — "each"

Cada means "each" and is invariable — it never takes a plural and is always followed by a singular noun.

Cada aluno recebeu um certificado.

Each student received a certificate. (cada + singular)

Custa dez reais cada um.

It costs ten reais each.

Common Mistakes

❌ Eu vi ninguém na rua.

Incorrect — a post-verbal negative needs 'não' too.

✅ Não vi ninguém na rua.

I didn't see anyone on the street.

❌ Eu comi tudo o bolo.

Incorrect — 'tudo' can't take a noun; with a noun you need 'todo'.

✅ Eu comi todo o bolo.

I ate the whole cake.

❌ Todas as crianças dormiu.

Incorrect — 'todas' is plural, so the verb must be plural too.

✅ Todas as crianças dormiram.

All the children slept.

❌ Não tem nada? Então tem algo.

Style slip — in speech Brazilians say 'alguma coisa', not 'algo'.

✅ Não tem nada? Então tem alguma coisa.

There's nothing? Then there's something.

❌ Alguem me ligou.

Spelling error — missing the accent on the stressed final é.

✅ Alguém me ligou.

Someone called me.

Key Takeaways

alguém / ninguém (people) and tudo / nada (things) are invariable — one form each.
A negative word after the verb requires não as well (Não vi nada); a negative word before the verb does not (Nada aconteceu). The negatives reinforce, never cancel.
tudo = "everything," stands alone, never changes. todo/toda/todos/todas = "every/all," needs a noun, must agree.
For "something" in speech, prefer alguma coisa over the more formal algo.

Now practice Portuguese

Reading grammar gets you part of the way. The exercises are where it sticks — free, no signup needed.

Start learning Portuguese→