Irregular Adjectives in French

In Brief

French adjectives agree with the noun they describe, but some very common ones do not form the feminine by simply adding -e. Learn beau → belle, nouveau → nouvelle, vieux → vieille, blanc → blanche, and long → longue as complete form families. Before a masculine singular noun beginning with a vowel sound, use bel, nouvel, or vieil: un bel homme, un nouvel ami, un vieil arbre.

Overview

An adjective is a word that describes a noun (a person, place, thing, or idea). In English, “beautiful” stays the same in “a beautiful garden” and “a beautiful house.” In French, an adjective normally agrees with its noun in gender (the noun’s masculine or feminine grammatical category) and number (singular or plural): un beau jardin but une belle maison.

The usual beginner pattern is to add -e for the feminine and -s for the plural. The adjectives in this article are irregular because their spelling changes more substantially. They are worth learning at A1 because they occur in ordinary descriptions: old buildings, new friends, white shirts, long journeys, and beautiful places.

Three adjectives need particular attention: beau, nouveau, and vieux. As well as masculine, feminine, and plural forms, each has an extra masculine singular form used to make pronunciation flow smoothly before a vowel sound. This extra form has no direct equivalent in English, so it is best learned as part of the whole family rather than as an isolated exception.

How It Works

The agreement rule

First identify the noun being described. Then choose the adjective form that matches it.

Noun	What to choose	Example
masculine singular	masculine singular form	un beau village
feminine singular	feminine singular form	une belle ville
masculine plural	masculine plural form	de beaux villages
feminine plural	feminine plural form	de belles villes

Gender belongs to the French noun, not necessarily to the real-world object. For example, histoire is feminine, so French requires une longue histoire. Number works more like English: a plural noun requires a plural adjective.

Beau, nouveau, and vieux

These three common adjectives have five written forms. The “before a vowel sound” form is masculine singular only.

Meaning	Masculine singular	Before vowel sound	Feminine singular	Masculine plural	Feminine plural
beautiful, handsome	beau	bel	belle	beaux	belles
new	nouveau	nouvel	nouvelle	nouveaux	nouvelles
old	vieux	vieil	vieille	vieux	vieilles

Use the ordinary masculine form before a consonant sound:

• un beau jardin — a beautiful garden
• un nouveau téléphone — a new phone
• un vieux quartier — an old neighbourhood

Use bel, nouvel, or vieil before a masculine singular noun beginning with a vowel or a mute h (an h that does not block the connection between words):

• un bel appartement — a beautiful apartment
• un nouvel étudiant — a new male student
• un vieil hôtel — an old hotel

The noun’s gender still controls the form. Before a feminine noun, use the feminine adjective even when the noun starts with a vowel: une belle actrice, une nouvelle école, une vieille amie. Do not use bel, nouvel, or vieil there.

The extra form is about the following sound, not merely the first written letter. Most vowel-initial words and words with mute h trigger it. However, an aspirated h (a traditional label for an h that blocks linking, although the h itself is not pronounced) behaves like a consonant: un beau héros, not un bel héros. Dictionaries normally mark words with aspirated h, and it is practical to learn this property with the noun.

Blanc and long

These adjectives have no special pre-vowel form, but their feminine spelling changes more than simply adding -e.

Meaning	Masculine singular	Feminine singular	Masculine plural	Feminine plural
white	blanc	blanche	blancs	blanches
long	long	longue	longs	longues

The change is audible as well as visible. In blanc, the final consonant is normally silent; in blanche, the ch is pronounced. Likewise, longue has a pronounced final consonant sound that is absent from the usual pronunciation of long. Hearing the masculine and feminine as a pair helps more than memorising spelling alone.

Position before the noun

The irregular form and adjective position are separate questions. Beau, nouveau, and vieux usually come before the noun, as do many common adjectives of beauty, age, goodness, and size. This is why their pre-vowel forms appear so often:

• un bel homme
• un nouvel emploi
• un vieil ami

Blanc usually follows the noun: une chemise blanche. Long can appear before or after the noun depending on phrasing and emphasis, though common expressions such as une longue histoire, un long voyage, and les cheveux longs are best learned as natural chunks. Agreement is required wherever the adjective stands.

Examples in Context

French	English	Note
C’est un bel homme.	He is a handsome man.	Bel before a masculine vowel sound
Nous visitons un beau village.	We are visiting a beautiful village.	Beau before a consonant
Elle habite dans une belle maison.	She lives in a beautiful house.	Feminine singular
Ce sont de beaux jardins.	They are beautiful gardens.	Masculine plural
J’ai rencontré un nouvel ami.	I met a new friend.	Nouvel before a vowel sound
Voici ma nouvelle collègue.	This is my new colleague.	Feminine singular
Ils achètent de nouveaux meubles.	They are buying new furniture.	Masculine plural
Une vieille femme attend le bus.	An old woman is waiting for the bus.	Feminine singular
Un vieil arbre pousse devant la maison.	An old tree grows in front of the house.	Vieil before a vowel sound
Nous marchons dans les vieux quartiers.	We are walking through the old neighbourhoods.	Masculine plural; vieux does not change in writing
Il porte une chemise blanche.	He is wearing a white shirt.	Blanche agrees with chemise
Les murs sont blancs.	The walls are white.	Masculine plural after the noun
C’est une longue histoire.	It is a long story.	Longue before a feminine noun
Elle a les cheveux longs.	She has long hair.	Masculine plural after the noun
Nous avons passé de longues heures à parler.	We spent long hours talking.	Feminine plural

Notice that English may use “new” in every translation, but French distinguishes nouveau, nouvel, nouvelle, nouveaux, and nouvelles. Build the French phrase from the French noun rather than translating the English adjective word by word.

Common Mistakes

Using the regular masculine form before a vowel sound

• Wrong: un beau homme
• Right: un bel homme
• Why: A masculine singular noun beginning with a vowel sound requires the special form bel. The same pattern gives un nouvel ami and un vieil appartement.

Using the pre-vowel form with a feminine noun

• Wrong: une bel actrice
• Right: une belle actrice
• Why: Bel is not a general vowel form; it is masculine singular. A feminine noun always takes belle, including before a vowel.

Forming the feminine by adding only -e

• Wrong: une beaue robe; une blouse blance; une longe route
• Right: une belle robe; une blouse blanche; une longue route
• Why: These forms involve a spelling change, not merely the regular -e ending. Memorise beau/belle, blanc/blanche, and long/longue as pairs.

Carrying the special singular form into the plural

• Wrong: des bels appartements; des nouvels amis
• Right: de beaux appartements; de nouveaux amis
• Why: Bel and nouvel are singular forms. Use beaux and nouveaux for masculine plurals. In careful standard French, des often becomes de before a plural adjective placed before the noun.

Choosing the form from the person speaking

• Wrong: Je suis une vieux femme.
• Right: Je suis une vieille femme.
• Why: The adjective agrees with the noun it describes, here feminine femme. The speaker’s wording does not override the noun’s grammatical gender.

Treating every written h in the same way

• Wrong: un bel héros
• Right: un beau héros
• Why: Héros has aspirated h, which blocks the pre-vowel form. Compare mute h in un bel hôtel. Learn uncertain cases from a dictionary or audio source.

Usage Notes

The masculine and feminine forms may sound more different than their English translations suggest. Pairing sound with spelling is especially useful for vieux/vieille and blanc/blanche. When listening, agreement can therefore help you infer the noun’s gender even if you missed its article.

With a plural adjective before a noun, written standard French commonly changes the indefinite article des to de: de beaux jours, de nouvelles idées, de vieux amis. In relaxed speech, you may also hear des, but de is the safe choice in formal writing. This article change does not affect adjective agreement.

Many fixed combinations place these adjectives before the noun: le Nouvel An (“New Year”), un beau jour (“one fine day”), un vieux monsieur (“an old gentleman”), and une longue journée (“a long day”). Learning these as complete phrases gives you both the correct form and natural word order.

Beyond the Basics / Advanced Use

You do not need to master the following distinctions at A1, but they explain forms you will meet later.

Nouveau and neuf can both translate as “new,” but they do not always mean the same thing. Nouveau often means new in a situation, newly acquired, or another one: mon nouveau téléphone can be a phone that is new to me. Neuf usually means newly made or unused and normally follows the noun: un téléphone neuf. The feminine is neuve. Context, not English alone, determines the best adjective.

Adjective position can also affect nuance. A frequent adjective before the noun may present a quality as part of the speaker’s overall description, while a position after the noun can make it more identifying or contrastive. With vieux, the usual neutral phrase is un vieil homme. Unusual post-noun placement may sound marked or belong to a specific contrast, so beginners should keep the common pre-noun order.

The pre-vowel forms historically prevent an awkward sequence of vowel sounds. They remain obligatory in standard phrases even though modern French has other ways of managing adjacent vowels. They are genuine adjective forms, not contractions: bel is not beau plus another word.

Finally, spelling and pronunciation do not always line up neatly in the plural. Vieux is written the same in masculine singular and plural, so the article and noun reveal the number: un vieux livre versus de vieux livres. Before a plural vowel-initial noun, liaison (the linking pronunciation of an otherwise silent final consonant) may produce a /z/ sound, as in de vieux amis. The written adjective is still vieux, never vieils.

Practice Tips

1. Learn five-cell families. Say and write beau, bel, belle, beaux, belles, then do the same for nouveau and vieux. Attach a noun to every form so the choice has a reason.
2. Sort nouns by their opening sound. Make two small lists: consonant sound (jardin, quartier) and vowel or mute-h sound (ami, arbre, hôtel). Build phrases with beau/bel, nouveau/nouvel, and vieux/vieil.
3. Practise from the noun outward. Instead of translating “a beautiful…,” look first at the French noun’s gender, number, and first sound. Then select the adjective form and finally check its usual position.

Related Concepts

• Prerequisite: BANGS Adjectives — reviews the common French adjectives that usually appear before the noun.