In French, the letters ille after a vowel are usually pronounced as a glide, close to the English y sound, as in fille – “girl” or famille – “family”. A small, fixed group of words breaks this pattern. In these words the two Ls are pronounced as an ordinary L, the way an English speaker would expect from the spelling alone. This group has not grown for centuries, so it can be learned in full.

The ville family

Ville – “city” or “town” and everything built on it keep the hard L rather than the glide heard in fille.

• Elle habite en ville. – “She lives in the city.”
• Le centre-ville est animé le soir. – “The city centre is lively in the evening.”
• Un petit village de pêcheurs. – “A small fishing village.”
• Les villageois se sont réunis sur la place. – “The villagers gathered in the square.”
• Ils ont acheté une villa au bord de la mer. – “They bought a villa by the sea.”
• Nous partons en villégiature chaque été. – “We go away on holiday every summer.”

Synonyms and alternatives: for ville, French also has cité – “city” and agglomération – “urban area”. For village, alternatives include bourg – “market town” and hameau – “hamlet”.

The same hard L appears in place names built on ville, including Lille, Deauville, Trouville and Séville (the French name for Seville, in Spain).

• Lille se trouve dans le nord de la France. – “Lille is in the north of France.”
• Ils ont visité Séville en avril. – “They visited Seville in April.”

The mille family

Mille – “thousand” and its derivatives also keep the hard L.

• Il y a mille façons de faire ce plat. – “There are a thousand ways to make this dish.”
• La ville compte deux millions d’habitants. – “The city has two million inhabitants.”
• L’entreprise vaut plusieurs milliards d’euros. – “The company is worth several billion euros.”
• Un millier de personnes ont assisté au concert. – “About a thousand people attended the concert.”
• Le vin porte le millésime 2018. – “The wine carries the 2018 vintage.”
• Cette tradition remonte au troisième millénaire avant notre ère. – “This tradition goes back to the third millennium BCE.”

The higher numbers built on the same pattern follow suit, including billion, trillion and quadrillion.

• Le budget de la mission dépasse un billion de dollars. – “The mission’s budget exceeds a trillion dollars.”

Note that French milliard corresponds to the English “billion”, while French billion corresponds to the English “trillion”. The spelling looks familiar, but the value is not the same.

The tranquille family

• Le village est très tranquille la nuit. – “The village is very quiet at night.”
• Il faut rester tranquille pendant l’examen. – “You must stay still during the exam.”
• Elle a pris un tranquillisant avant de dormir. – “She took a tranquilliser before going to sleep.”
• Cette pensée me tranquillise. – “This thought reassures me.”
• Ils vivent dans une tranquillité totale. – “They live in total tranquillity.”
• Parlez tranquillement, personne ne vous presse. – “Speak calmly, nobody is rushing you.”

Synonyms and alternatives: for tranquille, French also has calme – “calm” and paisible – “peaceful”.

Words from learned Latin vocabulary

A group of technical or literary words borrowed straight from Latin also escaped the glide. Most belong to medicine, law or biology.

• bacille – “bacillus”
• codicille – “codicil” (an addition to a will)
• imbécillité – “imbecility”, meaning stupidity or foolishness
• capillaire – “capillary”
• fibrille – “fibril”
• pénicilline – “penicillin”
• cyrillique – “Cyrillic”
• pusillanime – “faint-hearted” or “pusillanimous”

Example sentences:

• Le médecin a identifié le bacille responsable de la maladie. – “The doctor identified the bacillus responsible for the illness.”
• Le notaire a ajouté un codicille au testament. – “The notary added a codicil to the will.”
• Son imbécillité a surpris tout le monde. – “His stupidity surprised everyone.”
• Les vaisseaux capillaires irriguent la peau. – “Capillary vessels supply blood to the skin.”
• L’alphabet cyrillique sert à écrire le russe. – “The Cyrillic alphabet is used to write Russian.”

A few rarer botanical or zoological terms follow the same rule, among them scille (a flowering plant, squill), maxille (a mouthpart of an insect) and vexille (a term used in botany and heraldry). These are unlikely to come up outside specialist texts.

Verbs that keep the hard L

A handful of verbs from Latin verbs ending in -illare are pronounced with a hard L rather than the usual glide.

• distiller – “to distil”: L’alcool est distillé plusieurs fois. – “The alcohol is distilled several times.”
• instiller – “to instil”: Le professeur a su instiller le goût de la lecture. – “The teacher managed to instil a love of reading.”
• osciller – “to oscillate”: L’aiguille oscille entre deux valeurs. – “The needle oscillates between two values.”

The related nouns keep the same pronunciation: distillation – “distillation”, distillerie – “distillery”, instillation – “instillation”, and oscillation – “oscillation”.

A few similar verbs, such as vaciller – “to waver” and scintiller – “to sparkle”, were once pronounced with a hard L too, but today are usually said with the glide, like briller – “to shine”. The older hard L pronunciation still turns up occasionally among careful or older speakers, but it is considered dated.

Gilles and other proper nouns

Proper nouns follow the same exception. Gilles, a French first name, and Lille, the city in the north of France, both keep the hard L.

• Gilles habite à Lille depuis dix ans. – “Gilles has lived in Lille for ten years.”

A word with two accepted pronunciations

Pupille can mean “ward” (a child under guardianship) or “pupil” (of the eye). Dictionaries are divided on this one. Some give it the glide heard in fille, others allow the hard L heard in bacille. Both are treated as correct today.

Not to be confused with a single L

The hard L versus glide question only concerns the double L spelling, ille. A single L after i, as in facile – “easy”, utile – “useful”, or file – “queue”, is always pronounced as an ordinary L, with no exceptions to learn. The word imbécile – “stupid” falls into this second, much larger and entirely regular category, even though the related noun imbécillité has a double L and belongs to the exception list above.

Summary

• Ville, mille and tranquille, along with their many derivatives, form the core of this group.
• Learned or technical words borrowed from Latin, such as bacille, codicille and capillaire, follow the same pattern.
• The verbs distiller, instiller and osciller keep the hard L, while similar verbs such as vaciller have mostly shifted to the glide.
• The proper nouns Lille and Gilles also belong to this group.
• A single L, as in facile, is a separate and much larger pattern, always pronounced as an ordinary L.