Le Présent: Verbes en -ir (3e groupe, sans -iss-)

Not every -ir verb in French follows the finir pattern. A small set — about fifteen base verbs and their compounds — belongs to the 3^e groupe, the irregular bucket. These verbs end in -ir at the infinitive but do not take the -iss- infix in the plural, and they conjugate by patterns that diverge sharply from each other. Cruelly, this small set contains some of the most everyday verbs in the language: partir, sortir, dormir, ouvrir, offrir, venir, tenir. You cannot avoid them.

The good news is that this irregularity is not random. The fifteen verbs cluster into three families that share a single template each. Once you learn one verb from each family, you have effectively learned the whole family — sortir conjugates exactly like partir, couvrir exactly like ouvrir, retenir exactly like tenir. This page walks through all three patterns with full paradigms, examples, and the transfer errors that English speakers make most often.

Family 1: the partir type

The largest of the three families. The defining feature is that the singular forms drop the final consonant of the stem, while the plural forms restore it.

Take partir: the full stem is part-, but the -t is silent in je pars, tu pars, il part (where it is either dropped from the spelling or simply unpronounced) and audible again in nous partons, vous partez, ils partent. The same alternation appears in dormir (je dors /dɔʁ/ — silent m — versus nous dormons /dɔʁmɔ̃/ with the m back), sentir (je sens /sɑ̃/ versus nous sentons /sɑ̃tɔ̃/), and the others.

Full paradigm: partir (to leave)

The endings are -s, -s, -t, -ons, -ez, -ent — added not to the full infinitive stem (part-) but to a shortened stem (par-) in the singular, then to the full stem (part-) in the plural. So the system is:

• Singular stem: par-
  • -s, -s, -t → pars, pars, part
• Plural stem: part-
  • -ons, -ez, -ent → partons, partez, partent

Or, equivalently: drop the final consonant of the infinitive stem in the singular, restore it in the plural. The same template runs through the family.

Other partir-type verbs

The same template covers a tight family. The bolded letter is the consonant that drops in the singular and returns in the plural.

Family 2: the ouvrir type — -er endings on an -ir verb

This is the family that catches every learner off guard. Ouvrir, couvrir, découvrir, offrir, souffrir, cueillir all end in -ir at the infinitive, but their present-tense conjugation borrows the endings of the 1^er groupe wholesale: -e, -es, -e, -ons, -ez, -ent. There is no consonant alternation, no -iss-, no -s on the je form — just the regular -er pattern grafted onto an -ir infinitive.

Full paradigm: ouvrir (to open)

Notice the obligatory elision (j'ouvre, not je ouvre) and the liaison /z/ before nous, vous, ils, elles. These follow the standard rules — ouvrir begins with a vowel, so the same elision and liaison apply that you see with any vowel-initial verb. Notice too that the je form ends in -e, not -s: j'ouvre, not j'ouvres. This is the single most common spelling error English speakers make on this family.

Other ouvrir-type verbs

Family 3: the venir / tenir type

The third family is small (just two parent verbs and their many compounds) but extremely high-frequency. Venir and tenir share a more complex stem alternation: a diphthong shift between the singular/3pl forms and the nous/vous forms, plus a doubled -nn- in the third-person plural.

Full paradigm: venir (to come)

Three things to notice:

1. The vowel changes. The singular and 3pl have -ie- (viens, vient, viennent); the nous/vous forms have plain -e- (venons, venez). The /jɛ̃/ in the singular becomes /ə/ in nous/vous.
2. The 3pl doubles the n. Ils viennent is spelled with double -nn- and pronounced /vjɛn/ — the nasal vowel of the singular has reopened into an oral /ɛ/ + /n/.
3. The 3pl is audibly distinct. Unlike the finir and partir paradigms, where the 3pl can sometimes be confused with the singular if the listener misses the consonant, ils viennent /vjɛn/ is clearly different from il vient /vjɛ̃/ — the nasal vowel has unrolled into an oral one.

Tenir, and the compounds

Tenir (to hold) follows exactly the same pattern: je tiens, tu tiens, il tient, nous tenons, vous tenez, ils tiennent. So do all the compounds:

The three families side by side

To see the full landscape at a glance, here are model verbs from all three families lined up in the present indicative:

Three observations. First, the nous and vous forms are the most predictable across all three families — -ons and -ez are universal. Second, the je / tu forms diverge: partir ends in -s, ouvrir in -e (or -es), venir in -s. Third, the 3pl is where each family is most distinctive: partent /paʁt/, ouvrent /uvʁ/, viennent /vjɛn/.

Frequency and where to start

If you only have time to memorize three verbs from this group, take partir, ouvrir, venir — one model from each family. They are also among the highest-frequency verbs in the language: venir alone shows up in dozens of fixed expressions (venir de, aller et venir, à venir, bienvenue).

Closely behind the three model verbs in usefulness: sortir (to go out — pairs with sentir), dormir (to sleep), offrir (to give as a gift — central to the French "to give a present" idiom, since donner un cadeau sounds like a translation while offrir un cadeau is what natives say), and devenir (to become — the standard copula for change of state).

Common mistakes

Mistake 1: Adding -iss- to a 3^e-groupe -ir verb.

Mistake 2: Adding -s to the je form of ouvrir-type verbs.

Mistake 3: Forgetting the consonant alternation in partir-type verbs.

Mistake 4: Treating se souvenir as if it were souvenir (a noun).

Mistake 5: Wrong vowel in the nous/vous form of venir/tenir.

Mistake 6: Single n in the 3pl of venir/tenir.

Key takeaways

The 3^e-groupe -ir verbs are irregular but predictable within their families. The fifteen base verbs and their compounds split into three patterns:

1. The partir family drops the final consonant in the singular and restores it in the plural: partir, sortir, dormir, sentir, mentir, servir.
2. The ouvrir family uses 1^er-groupe endings on -ir infinitives: ouvrir, couvrir, découvrir, offrir, souffrir, cueillir.
3. The venir/tenir family has a vowel shift between singular/3pl (-ien-/-ienn-) and nous/vous (-en-), plus a doubled n in the 3pl: venir, devenir, tenir, retenir, soutenir, etc.

Memorize one model verb from each family, learn that compounds inherit the parent's pattern, and the rest comes together quickly. After this, the regular -re verbs are the next stop, and the high-frequency irregulars être and avoir deserve their own dedicated study.