French Liaison: When Sounds Connect

French liaison is one of the features that makes spoken French sound smooth and connected. It occurs when a normally silent final consonant is pronounced to link two words-but only under specific conditions. This article breaks down the rules of French liaison into three categories: mandatory, forbidden, and optional, so you can sound more natural and understand native speakers more easily.

LexiFr is available on iOS and Android. Download the app.

What is French liaison?

In French, many words end with a consonant that is normally not pronounced: the s in les, the t in petit, the n in un (when it nasalises the vowel). But when such a word is immediately followed by a word starting with a vowel or a mute h, that silent consonant often becomes spoken, linking the two words together. This linking is called liaison (from lier, to bind).

For example:

• les /le/ (silent s) + enfants /ɑ̃.fɑ̃/ → les‿enfants /le.z‿ɑ̃.fɑ̃/ (the s is pronounced /z/ and attaches to the next word)
• un /œ̃/ (nasal, no n sound) + ami /a.mi/ → un‿ami /œ̃.n‿a.mi/ (the n is pronounced /n/, and the nasal quality softens or disappears)

Liaison is not a random slip; it follows patterns that depend on grammar, word class, and register. The key is to know when to connect, when to leave a break, and when you have a choice.

Mandatory liaison: when you must connect

Certain grammatical contexts require liaison. If you skip it, the phrase may sound incorrect or incomplete. The most reliable mandatory cases are:

1. After a determiner
   Articles, demonstratives, possessives, and numbers that end with a silent consonant always trigger liaison with the following noun.

   • les amis → /le.z‿a.mi/ (the friends)
   • cet homme → /sɛ.t‿ɔm/ (this man)
   • mes enfants → /mɛ.z‿ɑ̃.fɑ̃/ (my children)
   • deux heures → /dø.z‿œʁ/ (two hours)

2. Between a pronoun and a verb, or a verb and a pronoun

   • nous aimons → /nu.z‿ɛ.mɔ̃/ (we like)
   • ont-ils → /ɔ̃.t‿il/ (have they)
   • allez-y → /a.le.z‿i/ (go there)

3. After a short preposition or adverb

   • dans un moment → /dɑ̃.z‿œ̃ mɔ.mɑ̃/ (in a moment)
   • très utile → /tʁɛ.z‿y.til/ (very useful)
   • sans arrêt → /sɑ̃.z‿a.ʁɛ/ (without stopping)

4. In certain fixed expressions

   • de temps en temps → /də tɑ̃.z‿ɑ̃ tɑ̃/ (from time to time)
   • vis-à-vis → /vi.z‿a.vi/ (face to face)

5. After the verb être in its third-person forms (est, sont) when followed by a vowel

   • il est arrivé → /i.l‿ɛ.t‿a.ʁi.ve/ (he arrived)
   • ils sont en retard → /il sɔ̃.t‿ɑ̃ ʁə.taʁ/ (they are late)

In these contexts, omitting the liaison would sound stilted or like a learner mistake.

Forbidden liaison: when you must not connect

Just as important as knowing when to link is knowing when not to link. A false liaison can be jarring or change the meaning. The main forbidden cases are:

1. Before a word beginning with an h aspiré
   Despite the vowel sound that follows, these words behave as if they start with a consonant. No liaison.

   • les haricots → /le a.ʁi.ko/ (the beans), never /le.z‿a.ʁi.ko/
   • en haut → /ɑ̃ o/ (upstairs), not /ɑ̃.n‿o/

2. After the conjunction et

   • et on → /e ɔ̃/ (and we/one), never /e.t‿ɔ̃/

3. After a singular common noun (unless it is part of a set phrase)

   • un chat orange → /œ̃ ʃa o.ʁɑ̃ʒ/ (an orange cat), not /œ̃ ʃa.t‿o.ʁɑ̃ʒ/
   • But in a compound like pot-au-feu, the liaison occurs (po.t‿o.fø).

4. Before onze, oui, and un (when un is a numeral)

   • les onze joueurs → /le ɔ̃z ʒwœʁ/ (the eleven players)
   • un oui timide → /œ̃ wi ti.mid/ (a timid yes)

5. After a proper name (with some poetic exceptions)

   • Jean arrive → /ʒɑ̃ a.ʁiv/ (Jean arrives), not /ʒɑ̃.n‿a.ʁiv/

6. In many cases after interrogative adverbs

   • Comment allez-vous ? → /kɔ.mɑ̃ a.le vu/ (How are you?), not /kɔ.mɑ̃.t‿a.le vu/
     (Though you may hear this from some speakers, it is not standard.)

A good rule of thumb: if you are not sure whether the h is mute or aspirated, check a dictionary. Most h’s are mute (liaison), but a few common ones-haricot, haut, héros, honte-are aspirated.

Optional liaison: register and choice

A large number of liaisons fall into the optional category. Making them adds a formal, polished tone; omitting them feels more conversational. The choice often reflects register. In a job interview or a speech, you might use more optional liaisons; with friends, fewer.

Common optional patterns include:

• After plural nouns when followed by an adjective or complement: des enfants‿heureux /de.z‿ɑ̃.fɑ̃.z‿œ.ʁø/ (happy children) – optional but very frequent.
• After forms of être other than third-person and after other auxiliary verbs: je suis‿arrivé /ʒə sɥi.z‿a.ʁi.ve/ (I arrived) – optional, leaning toward formal.
• After certain adverbs: vraiment‿intéressant /vʁɛ.mɑ̃.t‿ɛ̃.te.ʁɛ.sɑ̃/ (really interesting).
• After prepositions with more than one syllable: selon‿elle /sə.lɔ̃.n‿ɛl/ (according to her).

In everyday informal speech, you will often hear these liaisons dropped. The one exception is after plural nouns before an adjective-French speakers tend to make that liaison even in casual contexts, perhaps because les alone already ends in /z/.

If you overproduce optional liaisons, you may sound stiff; if you drop them entirely in a formal setting, you risk sounding careless. Paying attention to how natives handle them is the best teacher-why listening matters explains how training your ear is key to picking up these nuances.

Common mistakes with liaison

Even when you know the rules, a few pitfalls can trip you up.

Wrong consonant sound
When a silent consonant becomes pronounced, its sound often changes:

• s → /z/ (not /s/): les‿amis /le.z‿a.mi/ not /le.s‿a.mi/
• x → /z/: dix‿euros /di.z‿ø.ʁo/
• d → /t/: un grand‿arbre /œ̃ gʁɑ̃.t‿aʁbʁ/, not /gʁɑ̃.d‿aʁbʁ/
• g → /k/: un long‿hiver /œ̃ lɔ̃.k‿i.vɛʁ/ (rare, but in fixed expressions)

Inserting a forbidden liaison

• Saying et‿on /e.t‿ɔ̃/ instead of /e ɔ̃/ is a classic sign of a non-native speaker.
• Saying les‿haricots /le.z‿a.ʁi.ko/ will sound wrong to a French ear.

Omitting mandatory liaison

• nous‿avons /nu.z‿a.vɔ̃/ is compulsory. Saying /nu a.vɔ̃/ breaks the flow and marks you as a beginner.

A memory tip: listen and shadow

Liaison is primarily a spoken phenomenon, so reading about it only goes so far. The most effective way to internalize it is through repeated listening and imitation-a technique often called shadowing.

includes listening practice and a dedicated Shadowing feature that lets you hear words in connected speech and repeat them. By pairing the rules with consistent audio exposure, you gradually learn to produce liaisons automatically without overthinking.

To train at home: pick a short audio clip (a news headline, a podcast snippet), transcribe the liaisons you hear, then speak along with the recording, mimicking the rhythm and connections. Over time, your brain starts to predict where liaisons occur, much like a native speaker’s does. This practice directly supports your ability to build a richer French vocabulary, because correct pronunciation makes new words stick better and sound more natural when you recall them.

Practice: try these sentences

Mark the liaisons and read them aloud. The symbol ‿ shows where sounds connect.

1. Les‿amis de mes‿enfants sont‿arrivés.
   /le.z‿a.mi də me.z‿ɑ̃.fɑ̃ sɔ̃.t‿a.ʁi.ve/
   (My children’s friends have arrived.)

2. Nous‿avons‿un petit‿appartement.
   /nu.z‿a.vɔ̃.z‿œ̃ pə.ti.t‿a.paʁ.tə.mɑ̃/
   (We have a small apartment.)

3. Elle est‿allée chez‿elle.
   /ɛ.l‿ɛ.t‿a.le ʃe.z‿ɛl/
   (She went home.)

4. Ils‿ont acheté deux‿énormes‿oranges.
   /il.z‿ɔ̃ aʃ.te dø.z‿e.nɔʁ.mə.z‿ɔ.ʁɑ̃ʒ/
   (They bought two enormous oranges.)

5. Quand‿il arrive, on ne dit rien.
   /kɑ̃.t‿il a.ʁiv ɔ̃ nə di ʁjɛ̃/
   (When he arrives, we say nothing.)

Try saying these sentences several times, paying close attention to where the liaison happens and which consonant sound is produced. With practice, the rules will start to feel intuitive.