Contraction Errors | Portuguese (Portugal) Grammar

Portuguese requires you to fuse certain prepositions with the articles, demonstratives, and pronouns that follow them. These contractions are not stylistic — they are grammatically mandatory, and writing de o João instead of do João is a flat error, not a quaint alternative. English speakers routinely miss these fusions because English has nothing comparable: we say of the and in the as two separate words and never think about gluing them together. In Portuguese, separating the pieces sounds the way "I am going to the the park" would sound in English — broken.

This page catalogues every contraction you are required to make, the four or five places where learners most often slip, and the single diacritic mistake (missing à) that sinks otherwise good writing.

The four mandatory prepositions

Four prepositions — de, em, a, and por — contract with the definite articles o, a, os, as. If you see one of these prepositions directly before an article, you must fuse them. There are no exceptions in modern standard Portuguese.

Preposition	o	a	os	as
de (of, from)	do	da	dos	das
em (in, on, at)	no	na	nos	nas
a (to, at)	ao	à	aos	às
por (by, through)	pelo	pela	pelos	pelas

O carro do meu pai está avariado outra vez.

My dad's car has broken down again.

Pus as chaves em cima da mesa, não sei onde foram parar.

I put the keys on top of the table, I don't know where they ended up.

Vou ao médico amanhã de manhã.

I'm going to the doctor tomorrow morning.

Passámos pelo jardim no caminho para casa.

We went through the garden on the way home.

Why these are mandatory (and English isn't)

English preserves a separating article because the can be stressed or omitted independently: "of the park" vs "of a park" vs "of parks." Portuguese has chosen a different path — the article is so lightly pronounced after these prepositions that speakers long ago stopped perceiving it as a separate word. In speech, de o João would be indistinguishable from do João anyway, and the spelling reflects the reality.

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If you find yourself about to write de o, em a, a o, or por a, stop. These four combinations do not exist in written Portuguese.

The silent killer: the grave accent on à

When a (the preposition) meets a or as (the article), Portuguese uses a grave accent — à, às — not an acute. This is called crase (crasis) and it is the single most-missed diacritic in learner writing. À looks almost identical to a at a glance, which is exactly why learners forget it.

Vou à praia no sábado.

I'm going to the beach on Saturday.

Chegámos às oito em ponto.

We arrived at eight on the dot.

❌ Vou a praia no sábado.

Incorrect — missing the contraction and the grave accent

❌ Vou á praia no sábado.

Incorrect — wrong accent; à takes a grave, not an acute

The distinction between a and à is not cosmetic. Vou a praia would mean "I'm going [to] beach" with no article and would sound ungrammatical. Vou à praia means "I'm going to the beach." The grave accent is how Portuguese signals that two a's have merged into one.

Demonstratives also contract

The prepositions de and em also contract obligatorily with the demonstratives este, esse, aquele and their feminine/plural forms.

Preposition	este/esta	esse/essa	aquele/aquela	isto	isso	aquilo
de	deste/desta	desse/dessa	daquele/daquela	disto	disso	daquilo
em	neste/nesta	nesse/nessa	naquele/naquela	nisto	nisso	naquilo

Gosto muito deste café, é o melhor da zona.

I really like this coffee shop, it's the best in the area.

Não acredito naquilo que ele disse ontem.

I don't believe what he said yesterday.

Pensa bem nisso antes de decidir.

Think carefully about that before deciding.

The preposition a only contracts with the aquele series, producing another grave-accent form: àquele, àquela, àquilo.

Dei o livro àquela senhora de óculos.

I gave the book to that lady with glasses.

Personal pronouns: the dele/dela group

The preposition de fuses with the third-person pronouns ele, ela, eles, elas to form dele, dela, deles, delas. These are the standard ways to express possession when you want to say "his", "hers", or "theirs" unambiguously.

de +	contraction	meaning
ele	dele	his / of him
ela	dela	hers / of her
eles	deles	theirs (m.) / of them
elas	delas	theirs (f.) / of them

O livro dela está em cima da secretária.

Her book is on top of the desk.

A casa deles fica ao lado da minha.

Their house is right next to mine.

The preposition em also contracts with these pronouns in formal writing: nele, nela, neles, nelas. These are common and not at all marked.

Não confies nele, ele nunca aparece a horas.

Don't trust him, he never shows up on time.

Optional: de um, em um, and friends

With the indefinite articles um, uma, uns, umas, contraction is optional but common. In PT-PT, num, numa, nuns, numas (em + um) are standard and appear freely in both speech and formal writing — do not avoid them. The de + um contractions (dum, duma, duns, dumas) are more colloquial and tend to be written de um, de uma in formal registers, though they are perfectly acceptable in informal writing.

Preciso dum favor, se for possível.

I need a favor, if possible. (informal: dum is fine in speech and casual writing)

O resultado depende de um critério objetivo.

The result depends on an objective criterion. (formal: de um preferred over dum)

A reunião foi num hotel no centro de Lisboa.

The meeting was in a hotel in downtown Lisbon. (num is fully standard in any register)

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In PT-PT writing, num/numa is standard at any register. For the de series, prefer de um, de uma in formal writing and let dum, duma appear naturally in speech and informal prose. Both are correct; only the register of the de series shifts.

When NOT to contract

Contraction only happens when the preposition genuinely governs the article that follows. If the article belongs to a different phrase — for instance, the subject of a following clause — no contraction occurs.

É hora de a Ana chegar.

It's time for Ana to arrive. (no contraction — 'a Ana' is the subject of 'chegar', not the object of 'de')

Antes de os convidados chegarem, arrumámos a sala.

Before the guests arrived, we tidied the room. (no contraction — 'os convidados' is the subject of the infinitive)

This is subtle and a common source of genuine ambiguity even among native speakers. The underlying principle: contract when the article attaches to the preposition's own object; do not contract when the article belongs to a subject that just happens to sit after the preposition.

Common mistakes

❌ O livro de o João está em cima de a mesa.

Incorrect — missing contractions

✅ O livro do João está em cima da mesa.

João's book is on top of the table.

❌ Vou a a praia amanhã.

Incorrect — a + a must contract to à

✅ Vou à praia amanhã.

I'm going to the beach tomorrow.

❌ Comprei o bolo por o teu aniversário.

Incorrect — por + o must contract to pelo

✅ Comprei o bolo pelo teu aniversário.

I bought the cake for your birthday.

❌ Não gosto de esse restaurante.

Incorrect — de + esse must contract to desse

✅ Não gosto desse restaurante.

I don't like that restaurant.

❌ O carro de ele é novo.

Incorrect — de + ele must contract to dele

✅ O carro dele é novo.

His car is new.

Key takeaways

The four mandatory contracting prepositions are de, em, a, por. They contract with every definite article (o, a, os, as) and with the demonstratives este/esse/aquele and their neuters isto/isso/aquilo. The preposition de additionally contracts with ele/ela/eles/elas. The preposition a plus a/as produces à/às with a grave accent — miss that accent and you have misspelled the word. Contractions with the indefinite um/uma are optional and register-sensitive. Do not contract across phrase boundaries when the article attaches to a following subject, not to the preposition.