One of the trickiest aspects of French pronunciation for learners is liaison – the smooth linking of a normally silent final consonant to the beginning of the following word when that word starts with a vowel or a silent “h”. Knowing when to do a liaison and when to avoid it is key to sounding more natural and fluent in French.

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What Is a Liaison?

In French, many words end in consonants that are normally silent, such as:

• vous [vu]
• petit [pə.ti]
• grand [ɡʁɑ̃]

However, when the next word starts with a vowel sound (or a mute “h”), that final consonant often reappears to link the words smoothly.

Example:

• vous avez → [vu‿za.ve]
  (The normally silent s in vous is pronounced as [z])

This is what we call liaison.

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Obligatory Liaisons (Always Required)

These occur in certain grammatical contexts and should always be made:

1. Between a determiner and a noun

• les enfants → [lez‿ɑ̃.fɑ̃] (the children)
• un homme → [œ̃‿nɔm] (a man)

2. Between a pronoun and a verb

• nous avons → [nu‿za.vɔ̃] (we have)
• ils arrivent → [il‿za.ʁiv] (they arrive)

3. Between an adjective and a noun (when the adjective comes before the noun)

• petits enfants → [pə.ti‿zɑ̃.fɑ̃] (small children)
• grands arbres → [ɡʁɑ̃‿zaʁbʁ] (tall trees)

4. In fixed expressions

• états-unis → [e.ta‿zy.ni] (United States)
• de temps en temps → [də tɑ̃‿zɑ̃ tɑ̃] (from time to time)

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Optional Liaisons (Style/Formality Dependent)

These are common in formal speech but may be dropped in informal or casual conversation.

1. After plural nouns

• des enfants intelligents → [dez‿ɑ̃.fɑ̃ ɛ̃.te.li.ʒɑ̃] (intelligent children) – optional liaison between enfants and intelligents

2. After verbs (when the subject is a noun)

• Ils finissent à huit heures → [il fi.nis‿a ɥit‿œʁ] (They finish at eight o’clock) – both liaisons are optional

Note: Optional liaisons are often used by news anchors, politicians, or in formal settings.

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Forbidden Liaisons (Never Done)

Some liaisons are considered incorrect and can sound unnatural or even ungrammatical.

1. After a singular noun

• le président‿est ici – wrong
  le président est ici → [lə pʁe.zi.dɑ̃ ɛ.ti.si]

2. After “et” (and)

• un père et‿un enfant – wrong
  un père et un enfant → [œ̃ pɛʁ e œ̃n ɑ̃.fɑ̃] – no liaison after et

3. Before an aspirated ‘h’

Some words that begin with “h” do not allow liaisons. These are called aspirated h-words.

• les‿haricots – wrong
  les haricots → [le a.ʁi.ko] (beans) – no liaison because haricots begins with an aspirated h

Compare:

• les‿hommes → [lez‿ɔm] (men) – hommes starts with a mute h, so liaison is required

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Common Liaison Sounds

Here are the most common liaison consonants and how they are pronounced:

Final Letter	Liaison Sound	Example	Pronunciation
s, x	[z]	vous avez	[vu‿za.ve]
d	[t]	grand homme	[ɡʁɑ̃‿t‿ɔm]
n	[n]	bon ami	[bɔ̃‿na.mi]
t	[t]	tout à fait	[tu‿ta fɛ]
r	[ʁ]	premier étage	[pʁə.mje‿ʁ‿taʒ]

Note that in the case of s, x and d, the liaised consonant becomes a harder and harsher version of itself. For example, an s becomes a z sound, and a d becomes a t sound.