What this is
dormir has been sitting in your vocabulary since the very first lesson of this course, used quietly as “to sleep” without its conjugation ever being spelled out. This is where that gets fixed — and where you meet the four verbs that behave exactly the same way: partir (to leave), sortir (to go out), sentir (to feel or smell), and servir (to serve).
The previous concept taught you the -iss- family (finir, choisir, réussir), where the plural inserts an extra syllable that isn’t in the infinitive. This family is the opposite kind of surprise: nothing gets added, something gets removed, and only in the singular.
The rule
Drop the -ir from the infinitive and you get a full stem: dorm-, part-, sort-, sent-, serv-. The plural uses that stem exactly as it is. The singular chops the final consonant off first.
| dormir | partir | sortir | sentir | servir | |
|---|---|---|---|---|---|
| je | dors | pars | sors | sens | sers |
| tu | dors | pars | sors | sens | sers |
| il/elle/on | dort | part | sort | sent | sert |
| nous | dormons | partons | sortons | sentons | servons |
| vous | dormez | partez | sortez | sentez | servez |
| ils/elles | dorment | partent | sortent | sentent | servent |
Read down any column and the pattern is the same shape every time: a short, consonant-dropped stem for je/tu/il, and the full stem plus -ons/-ez/-ent for nous/vous/ils. Learn the shape once and all five verbs — and every other verb in this family — fall out of it for free.
Why it works this way
The dropped consonant isn’t random. Historically, French singular verb endings wore down to almost nothing in speech, and the spelling eventually caught up: dormir had a stem-final -m, but sound change simplified dor-m-s toward something closer to dor, and the written form settled on dors. The plural never underwent that reduction, because -ons/-ez/-ent gave the consonant a vowel to lean on, so it survived intact. That’s also exactly why the -iss- family sounds so different: those verbs preserve their stem everywhere and instead grow an extra syllable in the plural. Two families, two different historical fixes to the same problem — how to keep a verb pronounceable across six persons.
Edge cases
The consonant only disappears in the singular
dors, pars, sors, sens, sers — say any of these aloud and you’ll notice they’re all one syllable, ending in a vowel sound with the final letter barely there or silent. Move to the plural and the consonant is back in full voice: dormons, partons, sortons, sentons, servons. This isn’t optional or a spelling quirk you can skip — write je dorm or je sent and you’ve written something that doesn’t exist in French. The three singular persons (je/tu/il) are also identical to each other for every one of these verbs, exactly like the -iss- family’s singular — the difference between the two families only ever shows up in the plural.
partir vs. sortir vs. quitter
English uses “leave” for three situations French keeps strictly apart. Partir means to leave/depart, full stop — no destination or object needed: Je pars. Sortir means to go out — also no object: Je sors ce soir. Quitter (a regular -er verb, not part of this family at all) means to leave someone or something specific, and it always needs a direct object: Je quitte mon bureau, never a bare Je quitte. An English speaker’s instinct to say “I’m leaving” and reach for whichever verb feels closest is exactly what causes the mix-up — check first whether there’s an object. If there is, it’s quitter. If there isn’t, it’s partir or sortir depending on whether you’re departing altogether or just stepping out.
What English speakers get wrong here
The most common mistake is over-correcting from the -iss- family just learned: adding an -is/-it ending or inserting -iss- into these verbs’ plural, producing something like nous dormissons. These five verbs never take -iss- anywhere — that insertion belongs exclusively to the other -ir family, and mixing the two patterns up is the single most predictable error at this stage. Check the infinitive-to-nous-form test: if the real nous-form doesn’t have -iss- in it, don’t invent one.
The second mistake is using quitter without an object because English “I’m leaving” has none. Quitter is transitive full stop — if there’s nothing to quit, reach for partir instead.
The third is keeping the singular’s dropped consonant in writing where it doesn’t belong, or the reverse — dropping it in the plural. The consonant’s presence tracks the ending, not the meaning: it survives wherever a vowel follows it (-ons, -ez, -ent) and disappears wherever nothing does.