dum/duma/duns/dumas

Contraction Dum

Level 3

dum = de + um
duma = de + uma
duns = de + uns
dumas = de + umas

How It Works

The contraction dum and its variants are standard features of the Portuguese language used to streamline pronunciation and writing.

1. Usage and Register:
While you can always choose to say de um or dum, the contraction is extremely common in spoken Portuguese across all regions. In writing, it is very frequent in European Portuguese (Portugal). In Brazilian Portuguese, it is common in literature and journalism, though some formal academic or legal style guides may prefer the full form de um.

2. Article vs. Numeral:
The contraction dum is typically used when um functions as an indefinite article. When um is used as a numeral (meaning 'exactly one'), it is often better to keep the forms separate (de um) to avoid ambiguity and emphasize the quantity.

3. The Infinitive Rule (Crucial Exception):
You must not contract the preposition if the article introduces the subject of an infinitive verb. In these cases, the preposition belongs to the previous phrase, and the article belongs to the verb's subject. This applies to any infinitive construction where the noun or pronoun following the preposition acts as the subject.

  • Correct: O fato de um aluno chegar... (The fact of a student arriving...)
  • Incorrect: O fato dum aluno chegar...

4. Meaning:
There is no difference in meaning between de um and dum. The choice is purely stylistic, with the contraction often feeling more idiomatic and less 'stiff' in natural conversation.

Examples (4)

  1. Eu preciso duma ajudinha aqui.

    I need a little help here.

    Word by Word: I need of-a little-help here.

    The verb precisar de (to need) requires the preposition 'de', which here contracts with 'uma'.

  2. Ele é filho dum médico famoso.

    He is the son of a famous doctor.

    Word by Word: He is son of-a doctor famous.

    A standard possessive use where 'de' indicates origin or relationship.

  3. Gosto duns sapatos que vi na vitrine.

    I like some shoes I saw in the window.

    Word by Word: I-like of-some shoes that I-saw in-the window.

    The plural form 'duns' is used here with the verb 'gostar de'.

  4. Ela falou dumas amigas de infância.

    She spoke about some childhood friends.

    Word by Word: She spoke of-some friends of childhood.

    Here 'de' means 'about', contracting with the feminine plural 'umas'.

Common Mistakes

  • Contracting when the article is the subject of an infinitive.

    Antes dum homem falar, ele deve pensar.
    Antes de um homem falar, ele deve pensar.

    Because 'um homem' is the subject of the verb 'falar', you must keep 'de' and 'um' separate.

  • Thinking 'dum' is mandatory like 'do'.

    Eu gosto do carro. (Mandatory) / Eu gosto dum carro. (Optional)
    Eu gosto de um carro. (Also correct)

    Unlike 'do' (de+o), which is required, you can always use 'de um' instead of 'dum' if you want to be more formal or emphatic.

Words in This Pattern

dumdumadunsdumas