Contractions of French prepositions (à + le = au; à + les = aux; de + le = du; de + les = des)

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What are prepositional contractions in French?

Prepositional contractions are short forms that French makes when the prepositions à (to/at) and de (of/from) come directly before the definite articles le (the, masculine singular) or les (the, plural).

The basic combinations you need to know are:
- à + le → au
- à + les → aux
- de + le → du
- de + les → des

Other related forms you will see are:
- à + la → à la (no contraction: feminine singular)
- de + la → de la (no contraction: feminine singular)
- à + l' → à l' (elision before a vowel or mute h)
- de + l' → de l' (elision before a vowel or mute h)

These contractions are mandatory when the preposition is followed by a definite article (le or les). They are not optional spelling shortcuts.

When do I use them?

Use these contractions whenever a preposition (usually à or de) is immediately followed by a definite article before a noun. Common situations include:
- Direction or destination: Je vais au cinéma. (I am going to the cinema.)
- Location or position: Nous sommes au parc. (We are at the park.)
- Indirect objects with verbs that take à: Il parle au professeur. (He speaks to the teacher.)
- Origin or source with de: Je reviens du marché. (I am coming back from the market.)
- Possession expressed with de: Le livre du professeur. (The teacher's book.)

If the article is feminine singular (la), there is no contraction: Je vais à la bibliothèque. (I am going to the library.)

How are they formed?

Basic rules
à + le = au
  • Je vais au cinéma. (I am going to the cinema.)
  • Il donne le cadeau au garçon. (He gives the gift to the boy.)
  • On joue au tennis. (We play tennis.)

à + les = aux
- Je parle aux étudiants. (I speak to the students.)
- Elle écrit aux amis. (She writes to the friends.)
- Ils jouent aux cartes. (They play cards.)

de + le = du
- Le sac du professeur. (The teacher's bag.)
- Je viens du marché. (I come from the market.)
- Il parle du problème. (He is talking about the problem.)

de + les = des
- La couleur des murs. (The color of the walls.)
- Je reviens des vacances. (I am back from vacation.)
- Il a peur des chiens. (He is afraid of dogs.)

No contraction with la
- à + la stays à la: Elle va à la plage. (She is going to the beach.)
- de + la stays de la: Le nom de la rue. (The name of the street.)

Elision before a vowel or mute h
When the article (le or la) starts with a vowel sound or a mute h, le and la elide to l' and you write:
- à + l' : à l'école. (to the school) → Je vais à l'école. (I go to school.)
- de + l' : de l'ami. (of the friend) → Le livre de l'ami. (The friend's book.)

Note: l' stands for either le or la depending on the original gender.

Exceptions and special cases

When le/les are pronouns, not articles
The contraction rules apply only when le or les are definite articles before a noun. When le, la or les are object pronouns (replacing a noun), the rules are different.
  • Example with article (contract): Je parle au professeur. (I speak to the teacher.) Here "au" = à + le (the professor).
  • Example with pronoun (no contraction of a following preposition): Avant de le voir, je prépare des questions. (Before seeing him, I prepare questions.) In "de le voir", le is an object pronoun, not an article, so you do not form du.

Also, for indirect object pronouns you generally use lui / leur instead of a form like à + le:
- Je donne le livre au garçon. (I give the book to the boy.) → Je lui donne le livre. (I give him the book.)

Des vs. des (contraction vs. indefinite plural article)
The written form des can be either:
  • the contraction of de + les (meaning "of the" or "from the"), or
  • the plural indefinite article meaning "some" (e.g., I have some books).

Compare these two different sentences:
- Je parle des élèves. (I talk about the students.) Here des = de + les (the students are definite).
- J'ai des élèves. (I have students / I have some students.) Here des = plural indefinite article (some).

Context tells you which meaning applies.

Countries and place names
When place names use a definite article, contractions apply:
  • Masculine singular country: au Canada. (I go to Canada.) → Je vais au Canada.
  • Feminine singular country: en France. (I go to France.) → Je vais en France (no au; different rule for countries).
  • Plural country or region: aux États-Unis. (to the United States) → Je vais aux États-Unis.
  • From these places uses du / de la / des accordingly: Je viens du Japon. / Je viens de France. / Je viens des Pays-Bas.

Common mistakes to avoid

1. Writing à le or de le as if they were allowed
- Wrong: Je vais à le cinéma.
- Right: Je vais au cinéma.

2. Trying to contract with la (feminine singular)
- Wrong: *au mère (for à la mère)
- Right: Je parle à la mère.

3. Forgetting elision before a vowel or mute h
- Wrong: Je vais à le école.
- Right: Je vais à l'école.

4. Confusing des (contraction) with des (indefinite plural)
- Compare: Je parle des élèves. (about the students = de + les) vs. J'ai des élèves. (I have students = some)

5. Mixing up a (has) and à (to/at) in writing
- Il a un livre. (He has a book.)
- Il va à Paris. (He goes to Paris.)
Remember the accent on à.

6. Using du when de is required after certain structures (negation, quantities, adjectives before nouns)
This is a wider grammar area, but be aware that des (as an indefinite plural) often becomes de after negation or after certain expressions. That is different from the contraction of de + les. Example:


  • Affirmative: J'ai des amis. (I have friends.)

  • Negative: Je n'ai pas d'amis. (I do not have friends.)

Comprehensive examples grouped by meaning

Direction / destination / location
  • Je vais au marché. (I am going to the market.)
  • Nous allons à la piscine. (We are going to the pool.)
  • Il est à l'école. (He is at school.)
  • Elles reviennent des vacances. (They are returning from vacation.)
Speaking to or about people (indirect object and talking about)
  • Je parle au directeur. (I speak to the director.)
  • Elle écrit aux clients. (She writes to the clients.)
  • Je parle des problèmes. (I speak about the problems.)
Possession and descriptions
  • Le stylo du professeur. (The teacher's pen.)
  • La maison de la voisine. (The neighbor's house.)
  • La couleur des yeux. (The color of the eyes.)
Actions and infinitives with pronouns
  • Avant de le manger, lave-le. (Before eating it, wash it.) — here de + le does not contract because le is a pronoun.
  • Je veux essayer de l'ouvrir. (I want to try to open it.) — l' is elision of le or la before a vowel.
Fixed phrases and expressions
  • Au revoir. (Goodbye.) — au = à + le
  • Au lieu de. (Instead of.) — du = de + le
  • Du matin (as in time expressions: de 9h du matin). (in the morning)
  • Aux alentours de midi. (Around noon) — aux = à + les

Glossary

Preposition — a small word that shows relation in space, time or logic (in French: à, de, dans, sur, etc.). In English: to, of, from, in, on.

Definite article — the words le, la, les in French; they mean "the" in English.

Indefinite article — the words un, une, des in French; they mean "a/an" or "some".

Contraction — joining two words into one shorter form (e.g., à + le → au).

Elision — dropping a vowel and replacing it with an apostrophe before a word that starts with a vowel sound (e.g., le + école → l'école).

Mute h (h muet) — some French words start with an h that behaves like a vowel; elision works before those words (e.g., l'homme, l'hôtel). This is different from words with an aspirated h where elision is not used.

Object pronoun vs article — object pronouns replace nouns (le, la, les when placed before a verb; or lui, leur for indirect objects), while articles (le, la, les) go before nouns. Contraction rules apply to articles, not to pronouns.

Quick summary / cheat sheet

- Always contract when à or de is followed by the definite article le or les: à + le → au; à + les → aux; de + le → du; de + les → des.
- Do not contract with la (feminine singular): à la, de la.
- Use l' before vowel or mute h: à l', de l'.
- Remember that des can be either de + les (of the / from the) or the plural indefinite article (some); use context to decide.
- If you replace a noun with a pronoun, contraction rules for articles do not apply; pronoun forms (lui, leur) are used for indirect objects.

If you keep these rules in mind and pay attention to whether you have a definite article (le, la, les) or a pronoun, you will correct most errors with au/aux/du/des.

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