You’ve been studying French for a while. You’ve memorized your verb conjugations, you can tell your *passé composé* from your *imparfait*, and your vocabulary is growing. Yet, when you listen to native speakers, there’s still a disconnect. They speak with a certain musicality, a seamless flow that makes their words melt into one another. You say, “les amis,” carefully enunciating each word. They say, “lez-ami.”

What’s their secret? It’s a beautiful, and sometimes baffling, feature of French phonetics called liaison.

Liaison is the phonetic glue of spoken French. It’s the practice of pronouncing the normally silent final consonant of a word when the next word begins with a vowel sound. It’s not just a stylistic flourish; it’s a fundamental rule that separates stilted, textbook French from the fluid, natural language spoken every day. Mastering it is one of the biggest leaps you can make towards authentic fluency.

But fear not! While it might seem like a complex web of arbitrary rules, liaison can be broken down into three simple categories: Required, Forbidden, and Optional. Let’s dive in.

What Exactly Is Liaison?

At its core, liaison exists to make the language sound better. The French language has an aversion to what linguists call a *hiatus*—an awkward pause or glottal stop that occurs when one word ending in a vowel is followed by a word beginning with a vowel. Try saying “tu as” without any connection. It feels a bit clunky. Liaison smooths this over.

In the case of liaison, a consonant that is silent at the end of a word (like the ‘s’ in les, the ‘t’ in est, or the ‘n’ in un) comes alive. It bridges the gap to the next word, provided that word starts with a vowel or a silent ‘h’ (h muet).

• Les amis → “Le-z-ami”
• Vous êtes → “Vou-z-êtes”
• Un grand arbre → “Un gran-t-arbre”

Understanding the three categories is the key to unlocking this feature.

Category 1: Required Liaison (Les Liaisons Obligatoires)

These are the “must-do” liaisons. Omitting them will sound incorrect and unnatural, and can sometimes even lead to misunderstandings. Think of these as the non-negotiable foundation of your spoken French. You should always make a liaison in these situations:

Between a Determiner and a Noun

This is the most common and important liaison. Articles (like un, les, des) and other determiners (like mon, ces, quels) always link to the noun they modify.

• les amis → le-z-amis (the friends)
• un avion → un-n-avion (an airplane)
• mes enfants → me-z-enfants (my children)
• cet homme → ce-t-homme (this man)

Between an Adjective and a Noun

When an adjective comes before the noun (which is common for short, descriptive adjectives), the liaison is required.

• un petit enfant → un peti-t-enfant (a small child)
• de grands arbres → de gran-z-arbres (big trees)
• le premier étage → le premie-r-étage (the first floor)

Between a Pronoun and a Verb

Subject pronouns always link to their verbs. This is especially true for pronouns like nous, vous, ils, elles, and on.

• nous avons → nou-z-avons (we have)
• vous êtes → vou-z-êtes (you are)
• ils ont → il-z-ont (they have)
• on arrive → on-n-arrive (we are arriving)

This also applies in inverted questions, when the pronoun follows the verb:

• Est-il ici ? → Est-i-l-ici ? (Is he here?)
• Ont-elles faim ? → Ont-elle-z-faim ? (Are they hungry?)

In Common Set Phrases and After Short Adverbs

Many fixed expressions and short adverbs have required liaisons that are baked into the phrase.

• très intéressant → trè-z-intéressant (very interesting)
• plus ou moins → plu-z-ou moins (more or less)
• de temps en temps → de temp-z-en temps (from time to time)
• c’est-à-dire → c’es-t-à-dire (that is to say)

Category 2: Forbidden Liaison (Les Liaisons Interdites)

Just as important as knowing when to make a liaison is knowing when *not* to. Making a liaison in these contexts is a classic mistake that instantly flags you as a non-native speaker. Avoid connecting words in these situations:

After a Singular Noun

Never connect a singular noun to the adjective or adverb that follows it. There is a clean break.

• un soldat // anglais (an English soldier) – NOT “solda-t-anglais”
• un projet // intéressant (an interesting project) – NOT “proje-t-intéressant”

After “et” (and)

The ‘t’ in et is always, always silent. It never creates a liaison. This is a crucial rule to remember.

• un homme et // une femme (a man and a woman)
• J’ai lu un livre et // il était bon. (I read a book and it was good.)

Before an Aspirated ‘H’ (H Aspiré)

This is a tricky one. In French, the letter ‘h’ is always silent, but it comes in two flavors: the *h muet* (mute h), which allows liaison, and the *h aspiré* (aspirated h), which acts like a consonant and blocks it. You unfortunately have to memorize which words start with an *h aspiré*. Common examples include héros (hero), haricots (beans), and hauteur (height).

• Liaison Allowed (h muet): les hommes → le-z-hommes
• Liaison Forbidden (h aspiré): les // héros → le // héros (NOT le-z-héros)
• Liaison Forbidden (h aspiré): les // haricots → le // haricots (NOT le-z-haricots)

After Certain Adverbs and Pronouns

Never make a liaison after interrogative adverbs like quand, comment, or combien when followed by a verb in an inversion.

• Comment // allez-vous ? (How are you?)
• Quand // est-il arrivé ? (When did he arrive?) *An exception is the common phrase “Quand est-ce que…?” where the liaison is made: “quan-t-est-ce que…?”*

Category 3: Optional Liaison (Les Liaisons Facultatives)

This is where things get interesting. Optional liaisons are the domain of style, register, and personal preference. Using them makes your speech sound more formal, elevated, and poetic. Omitting them is perfectly fine and is the norm in casual, everyday conversation.

You might hear these in a presidential address, a university lecture, or a poetry reading, but you’re less likely to hear them among friends at a café.

• After a plural noun + adjective:
  • Casual: des enfants // intelligents
  • Formal: des enfants-z-intelligents
• After forms of être (to be):
  • Casual: Je suis // ici.
  • Formal: Je sui-z-ici.
• After verbs like pouvoir or vouloir:
  • Casual: Je veux // un autre.
  • Formal: Je veu-x-un autre.

Our advice for learners? Don’t worry too much about these at first. Focus on mastering the required and forbidden liaisons. As you listen to more French, you’ll develop a natural feel for when these optional liaisons are used.

The Surprising Sound Changes of Liaison

One final, fascinating detail is that the sound of the consonant can change during liaison. It doesn’t always sound the way it’s spelled.

• S or X → [z] sound: This is the most common one. Les amis (le-z-ami), deux ans (deu-z-ans).
• D → [t] sound: Un grand homme (un gran-t-homme).
• F → [v] sound: Neuf ans (neu-v-ans).

Your Path to Fluent Liaison

Liaison is the rhythm and soul of spoken French. It’s what transforms a series of disconnected words into a coherent, musical phrase. While the rules might seem daunting, the path forward is clear:

1. Master the Required Liaisons. Focus on determiners + nouns and pronouns + verbs. This will give you the biggest return for your effort.
2. Memorize the Forbidden Liaisons. Especially “et” and common “h aspiré” words. Avoiding these mistakes is crucial.
3. Listen Actively. Pay close attention to how native speakers connect their words in movies, podcasts, and songs. Mimic what you hear.
4. Don’t Stress the Optional Ones. For now, just be aware they exist. Your intuition for them will grow with time and exposure.

Embrace the liaison. It may be a secret, but it’s one you can learn. With a little practice, you’ll stop just speaking French words and start speaking French music.