Avoiding Hiatus in French

General Principle

French generally seeks to avoid the meeting of two consecutive vowel sounds. This phenomenon is called a hiatus.

To make pronunciation smoother and more fluid, French uses several mechanisms:

• elision;
• liaison;
• special forms of determiners;
• the appearance of semivowels (glides);
• certain spelling changes.

The goal is always the same:

to facilitate the transition between sounds and avoid a clash between two vowels.

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Summary Table

Situation	Theoretical Form	Actual Form	Mechanism
Pronoun + vowel	je habite	j’habite	Elision
Article + vowel	le ami	l’ami	Elision
Article + silent H	le homme	l’homme	Elision
Demonstrative + vowel	ce arbre	cet arbre	Form change
Feminine possessive + vowel	ma amie	mon amie	Form change
Si + il	si il	s’il	Contraction
Plural determiner + vowel	les amis	les amis (pronounced lay-zah-mee)	Liaison
Verb voir	voi-ons	voyons	Semivowel insertion
Verb étudier	étudi-ons	étudions	Semivowel insertion
Verb envoyer	envoi-ons	envoyons	Semivowel insertion

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1. Elision

Definition

Elision consists of dropping a final vowel before a word beginning with a vowel or a silent H.

Examples

Full Form	Actual Form
je aime	j’aime
je habite	j’habite
le ami	l’ami
la école	l’école
ce est	c’est
ne est pas	n’est pas
de accord	d’accord
que elle	qu’elle

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Words That Commonly Undergo Elision

• je → j’
• le → l’
• la → l’
• ce → c’
• ne → n’
• de → d’
• que → qu’

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2. Silent H and Aspirated H

Silent H (H muet)

The H is not pronounced and does not block elision.

Therefore, elision takes place.

Examples

• l’homme
• l’hôtel
• l’habitude
• j’habite
• l’histoire

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Aspirated H (H aspiré)

The H is still not pronounced, but it blocks elision and liaison.

Examples

• le héros
• le haricot
• la honte
• le hasard
• le hibou

We say:

✅ le héros

❌ l’héros

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3. Possessive Adjectives Before a Vowel

To avoid hiatus, feminine possessive adjectives change form before a vowel.

Before a Consonant	Before a Vowel
ma sœur	mon amie
ma voiture	mon auto
ta sœur	ton amie
sa sœur	son ancienne collègue

The noun remains feminine.

The change exists solely to facilitate pronunciation.

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4. Demonstrative Adjectives

Before a Consonant	Before a Vowel
ce livre	cet arbre
ce garçon	cet étudiant
ce musée	cet hôtel

The form cet prevents the awkward sequence between ce and a following vowel.

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5. The Contraction “s’il”

French avoids:

❌ si il

and instead uses:

✅ s’il

Examples:

• s’il vient
• s’il pleut
• s’ils arrivent

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6. Liaison

Liaison creates an intermediate sound between two words.

Examples

Spelling	Pronunciation
les amis	lay-zah-mee
un ami	un-nah-mee
nous avons	noo-zavon
ils arrivent	eel-zariv

The liaison consonant acts as a bridge between two vowel sounds.

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7. Semivowels (Glides)

French often transforms a vowel into a semivowel.

The Three Main French Semivowels

Symbol	Example
[j]	bien, pied, voyons
[w]	oui, moi, loi
[ɥ]	lui, nuit, huit

These sounds help avoid or soften hiatus.

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8. The Case of “voir”: nous voyons

Why do we write “voyons”?

One could theoretically imagine:

• voi + ons

The succession of vowels would be less natural.

French instead introduces the semivowel [j], represented by the letter y.

This produces:

• nous voyons
• vous voyez

Pronunciation:

• vo-yons
• vo-yez

The letter Y functions as a transition between vowels.

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9. Other Similar Verbs

Infinitive	Conjugated Form
voir	nous voyons
envoyer	nous envoyons
nettoyer	nous nettoyons
employer	nous employons

In all these cases, the semivowel [j] facilitates pronunciation.

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10. Verbs Ending in -ier

Examples:

• étudier → nous étudions
• oublier → nous oublions
• marier → nous marions
• crier → nous crions

The letter i is pronounced as the semivowel [j].

For example:

• nous étudions → ay-too-dee-yon
• nous crions → cree-yon

The hiatus is therefore greatly reduced.

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Exceptions: When French Accepts Hiatus

French does not always eliminate the meeting of two vowels.

Certain words deliberately preserve a hiatus.

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1. Words of Learned or Classical Origin

• créer
• réagir
• réélire
• réorganiser
• coopérer
• aérodrome

Pronunciation:

• cré-er
• ré-a-gir
• ré-é-lire

The vowels belong to separate syllables.

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2. Words with a Diaeresis (Tréma)

The diaeresis explicitly indicates that two vowels must be pronounced separately.

Examples

Word	Approximate Pronunciation
Noël	No-el
naïf	na-eef
haïr	ha-eer
maïs	ma-ees
aiguë	ay-goo-uh

The diaeresis is a graphic marker of hiatus.

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3. Certain Common Words

• chaos
• cacao
• poète
• poésie
• océan
• lion

In these words, the succession of vowel sounds is accepted.

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4. Prefixes Such as ré-, pré-, co-

Hiatus is often preserved in order to maintain the structure and meaning of the word.

Examples

• réécrire
• réouvrir
• réorganiser
• réajuster
• coopérer
• coédition

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What You Should Remember

French does not completely forbid hiatus, but it has a strong tendency to avoid it.

To do so, it uses:

1. Elision: j’aime, l’école;
2. Special forms: mon amie, cet arbre;
3. Contractions: s’il;
4. Liaison: les amis;
5. Semivowels (glides): voyons, étudions.

However, some words deliberately preserve hiatus, especially:

• words with a diaeresis (Noël, maïs, haïr);
• words formed with certain prefixes (réécrire, réagir);
• words whose historical development has preserved separate vowels (poésie, chaos, océan).

The rule can therefore be summarized as follows:

French generally prefers to avoid hiatus, but it accepts it when it is necessary to distinguish syllables, preserve meaning, or respect the historical structure of a word.