Most French adverbs are formed by adding -ment to the feminine form of the adjective: lent → lentement, sérieux → sérieusement, heureux → heureusement. However, adjectives ending in -ent or -ant follow a different pattern. Instead of using the feminine form, they drop the final -t and add -mment directly to the stem.

Formation rules

1. Adjectives ending in -ent form adverbs in -emment.
   Example: évident → évidemment
   The ending -ent changes to -emment.
2. Adjectives ending in -ant form adverbs in -amment.
   Example: brillant → brillamment
   The ending -ant changes to -amment.

This pattern is consistent and applies regardless of whether the adjective is masculine or feminine.

Comparison with regular adverb formation

In the regular system:

• You take the feminine form of the adjective.
• You then add -ment.

Examples:

• lent (masc.) → lente (fem.) → lentement
• franc (masc.) → franche (fem.) → franchement
• doux (masc.) → douce (fem.) → doucement

For adjectives in -ent and -ant, you do not form the feminine version. Instead, you keep the masculine stem and make the substitution:

• -ent → -emment
• -ant → -amment

Examples

Adjectives in -ant → adverbs in -amment

• brillant → brillamment (Brilliant → Brilliantly)
• constant → constamment (Constant → Constantly)
• méchant → méchamment (Mean → Meanly)
• éloquent → éloquemment (Eloquent → Eloquently)
• prudent → prudemment (Prudent → Prudently)

Adjectives in -ent → adverbs in -emment

• récent → récemment (Recent → Recently)
• évident → évidemment (Evident → Obviously)
• patient → patiemment (Patient → Patiently)
• suffisant → suffisamment (Sufficient → Sufficiently)
• intelligent → intelligemment (Intelligent → Intelligently)

Pronunciation

The endings -emment and -amment are pronounced exactly the same: [amɑ̃].
This means that évidemment and brillamment rhyme perfectly, despite being spelled differently.

This identical pronunciation results from historical sound changes. The doubled m simply marks a nasal vowel; it does not indicate a double consonant in pronunciation. The distinction between -emment and -amment is therefore purely orthographic, not phonetic.

Common pitfalls

• Learners sometimes overgeneralize and add -ment directly, writing évidentement instead of évidemment. Such forms are incorrect.
• Because pronunciation is the same for both -amment and -emment, spelling must be memorized.
• Not every adjective in -ent or -ant forms an adverb naturally. For example, absent does not produce absemment. Instead, another structure (en son absence) is used.

Summary

• Regular adverbs: add -ment to the feminine adjective.
• Adjectives ending in -ent: replace -ent with -emment.
• Adjectives ending in -ant: replace -ant with -amment.
• Both endings are pronounced [amɑ̃].
• Spelling differs, but pronunciation does not.