Le Double-i en Imparfait et Subjonctif | French Grammar

Few features of written French trip up advanced learners as reliably as the double i of the imparfait and subjunctive nous/vous forms: nous étudiions, vous oubliiez, que nous riions, que vous payiez. They look wrong. They sound exactly the same as the present-tense forms with a single i. And yet they are the only correct spelling, and a missing i is a real grammatical error that signals "this writer didn't quite finish learning French."

This page explains why the double i exists, which verb classes require it, where it appears in the conjugation table, and why it is almost impossible to hear. Once you understand the logic — that the second i is the conjugation ending itself, layered on top of a stem that already ends in i — you stop perceiving it as a typo and start producing it automatically.

Why two i's

The mechanism is mechanical addition. Start with a verb whose stem already ends in i, and add the imparfait or subjunctive endings -ions and -iez on top.

Take étudier (to study). The stem of the present tense is étudi- — you can see this directly in nous étudions (the -ons attaches to étudi-). Now add the imparfait endings, which are -ais, -ais, -ait, -ions, -iez, -aient.

Pronoun	Stem + ending	Final spelling	Single or double i
je	étudi- + -ais	étudiais	one i
tu	étudi- + -ais	étudiais	one i
il	étudi- + -ait	étudiait	one i
nous	étudi- + -ions	étudiions	two i's
vous	étudi- + -iez	étudiiez	two i's
ils	étudi- + -aient	étudiaient	one i

The stem provides the first i. The ending begins with the second i. French writes both — without simplifying — because both i's are doing morphological work: the first marks the stem identity (étudi-), the second marks the person/tense (-ions = 1st plural imparfait/subjunctive). Drop one and you lose information; the spelling stops being a faithful spell-out of the morphology.

Quand nous étudiions ensemble à la fac, on travaillait jusqu'à minuit.

When we used to study together at university, we'd work until midnight.

This is the kind of sentence that gets corrected by every literate French speaker who reads nous étudions instead of nous étudiions. The first means "we are studying" (present), the second means "we were studying" (imparfait) — same pronunciation, completely different tense.

The pronunciation problem

Here is the maddening part: in everyday spoken French, nous étudions (present) and nous étudiions (imparfait) are pronounced almost identically. Both come out as something close to /nu zety.djɔ̃/. Careful speakers may lengthen the i slightly in the imparfait — nu ze.ty.di.jɔ̃ — but in normal speech you cannot reliably tell them apart by ear.

This means the only place the imparfait of these verbs is fully visible is in writing. In speech, context determines which tense is meant. In writing, the double i is the signal. If you write a single i in those forms, you've defaulted to the present.

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If you have ever wondered why French has so many homophones that look different in writing, the imparfait nous/vous forms of -ier verbs are a perfect case study. The orthography preserves a distinction that the modern pronunciation has lost. This is one of the ways French writing carries grammatical information the spoken language no longer signals on its own.

Which verbs are affected

Any verb whose present-tense stem ends in i or y, plus a few related cases. There are three big classes.

Class 1: -ier verbs

Verbs ending in -ier in the infinitive have a stem ending in i. The list is long and high-frequency:

étudier, apprécier, oublier, crier, prier, plier, négocier, copier, marier, vérifier, identifier, modifier, simplifier, signifier, justifier, multiplier, publier, remercier.

The conjugation pattern for oublier (to forget):

Tense	Form	Spelling
Present nous/vous	nous oublions, vous oubliez	one i
Imparfait nous/vous	nous oubliions, vous oubliiez	two i's
Subjunctive nous/vous	que nous oubliions, que vous oubliiez	two i's
Other persons (imparfait)	j'oubliais, tu oubliais, il oubliait, ils oubliaient	one i

Il faut que nous oubliions cette histoire et que nous passions à autre chose.

We need to put this story behind us and move on.

Nous appréciions beaucoup ses conseils quand nous étions plus jeunes.

We really appreciated his advice when we were younger.

Class 2: -yer verbs

Verbs in -yer have a stem ending in y. In the nous/vous forms where the next vowel is a hard consonant or o, the y is kept. Importantly, the imparfait/subjunctive nous/vous endings start with -i-, and the spelling keeps both letters: y + i.

Verbs: employer, envoyer, nettoyer, essayer, payer, balayer, ennuyer, appuyer, essuyer.

Tense	Employer (to use, employ)
Present nous/vous	nous employons, vous employez
Imparfait nous/vous	nous employions, vous employiez
Subjunctive nous/vous	que nous employions, que vous employiez

Note: this is not technically a "double i" — it's y + i. But it's the same logical pattern (stem-final vowel + ending-initial vowel both written) and the same kind of trap. Learners write nous employons in both tenses and miss the imparfait/subjunctive -i-.

À l'époque, nous employions une assistante deux jours par semaine.

At the time we used to employ an assistant two days a week.

Il faut que vous essayiez ce restaurant, il est excellent.

You really should try this restaurant, it's excellent.

Class 3: -iller and -illir verbs

Verbs whose stem ends in -ill- (a sound roughly /j/) follow the same pattern, because the -i- of the ending appears on top of the ill:

Verbs: travailler, briller, conseiller, réveiller, surveiller, cueillir, accueillir.

Tense	Travailler (to work)
Present nous/vous	nous travaillons, vous travaillez
Imparfait nous/vous	nous travaillions, vous travailliez
Subjunctive nous/vous	que nous travaillions, que vous travailliez

Quand nous travaillions dans le même bureau, on prenait toujours le café ensemble.

When we worked in the same office, we always had coffee together.

Class 4: -rire verbs (rire, sourire)

These are also affected because the stem is ri- / souri-:

nous rions (present, one i) vs nous riions (imparfait, two i's)
vous riez (present, one i) vs vous riiez (imparfait, two i's)

Nous riions tellement fort que les voisins ont frappé au mur.

We were laughing so hard the neighbors banged on the wall.

The subjunctive parallel

Because the imparfait endings and the subjunctive nous/vous endings are identical (-ions, -iez), every verb that takes a double i in the imparfait nous/vous also takes one in the present subjunctive nous/vous.

Verb	Présent	Imparfait	Subjonctif présent
étudier	nous étudions	nous étudiions	que nous étudiions
employer	nous employons	nous employions	que nous employions
travailler	nous travaillons	nous travaillions	que nous travaillions
rire	nous rions	nous riions	que nous riions
payer	nous payons	nous payions	que nous payions

This is a happy coincidence pedagogically: once you've mastered the imparfait double i, the subjunctive comes free.

Mon père voudrait que nous étudiions le droit, mais ma sœur préfère la médecine.

My father would like us to study law, but my sister prefers medicine.

Il faut absolument que vous payiez cette facture avant la fin du mois.

You absolutely have to pay this bill before the end of the month.

Verbs that do not double the i

Verbs whose present-tense stem does not end in i or y don't have this issue — there is no second i to add to a final i. The imparfait/subjunctive nous/vous simply have the regular -ions / -iez endings:

Verb	Imparfait nous/vous	Subjonctif nous/vous
parler	nous parlions, vous parliez	que nous parlions, que vous parliez
finir	nous finissions, vous finissiez	que nous finissions, que vous finissiez
prendre	nous prenions, vous preniez	que nous prenions, que vous preniez
faire	nous faisions, vous faisiez	que nous fassions, que vous fassiez
aller	nous allions, vous alliez	que nous allions, que vous alliez

The point: the double i is not a quirk of the imparfait or subjunctive endings themselves. It's a side-effect of stacking those endings on a stem that happens to end in i.

Source-language comparison

English doesn't have anything quite like this — most English inflection is suffixal (verb + -ed, verb + -ing) and English doesn't run into spell-out collisions where two morphemes share a vowel. The closest English analogue is the e at the end of stems before -ing: fly + -ing → flying (drop the y? change to i? In fly, y changes to i and an e gets inserted in some forms). But it's nowhere near as systematic as the French double i.

For Spanish, Italian, and Portuguese speakers, the French double i is genuinely unusual. Spanish has nothing like it: nosotros estudiamos in present and imperfect (nosotros estudiábamos) doesn't show any spelling collision. Italian similarly avoids the pile-up by spelling differently in each tense. French is unique in preserving both morphemes on the page even when the resulting sequence is visually awkward.

For English speakers, the most useful framing is: the second i is the ending, not a typo. Once you internalize that, you'll start expecting it.

Common Mistakes

❌ Quand nous étudions à Paris, nous sortions tous les soirs.

Ambiguous/incorrect — the writer probably meant the imparfait, which is étudiions with two i's.

✅ Quand nous étudiions à Paris, nous sortions tous les soirs.

When we were studying in Paris, we used to go out every evening.

❌ Il faut que nous oublions cette dispute.

Incorrect — the subjunctive needs two i's: oubliions.

✅ Il faut que nous oubliions cette dispute.

We need to forget this argument.

❌ Vous payez vos impôts en retard à l'époque.

Incorrect — for the imparfait you need 'vous payiez', not 'vous payez' (which is present).

✅ Vous payiez vos impôts en retard à l'époque.

You used to pay your taxes late back then.

❌ Quand nous travaillons dans cette usine, c'était dur.

Incorrect — imparfait of travailler is 'nous travaillions' (two i's).

✅ Quand nous travaillions dans cette usine, c'était dur.

When we worked in that factory, it was hard.

❌ Le prof veut que nous appréciez la littérature française.

Two errors: appréciez (not appréciions) and the wrong person — 'que nous appréciions' or 'que vous appréciiez'.

✅ Le prof veut que nous appréciions la littérature française.

The teacher wants us to appreciate French literature.

Key takeaways

The double i appears in the nous and vous forms of the imparfait and present subjunctive — and only there — for verbs whose stem ends in i or y.
The first i is the stem (étudi-, oubli-, ri-, empl*oy-), the second is the inflectional ending (-ions, -iez*). Both are written because both carry meaning.
The double i is virtually inaudible: in normal speech, nous étudions and nous étudiions sound identical. The spelling preserves a distinction that pronunciation has lost.
It affects all -ier verbs (étudier, oublier, apprécier, vérifier, multiplier), -yer verbs (employer, payer, essayer), -iller verbs (travailler, conseiller, surveiller), and -rire verbs (rire, sourire).
The pattern is the same in the imparfait and the present subjunctive, because both have -ions, -iez endings.
For verbs with stems that don't end in i or y, no double i occurs: nous parlions, que nous fassions, nous prenions.
See verbs/imparfait/spelling-changes-imparfait and verbs/subjunctive/spelling-changes-subj for the full paradigms.

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