French Stem-Changing Verbs

French stem-changing verbs are conjugated with the same endings as regular -er verbs but have two different radicals or stems. Stem-changing verbs are sometimes also called boot verbs or shoe verbs because if you circle the forms that have stem changes in a certain style of conjugation table, the resulting shape looks like a boot or shoe.

The Stem-Changing Verbs

There are six different kinds of stem-changing verbs based on the final four letters of the verb. The actual spelling change required for each type of stem-changing verb is different, such as y changes to i in -oyer verbs and é changes to è in -é_er verbs, but the tenses and grammatical persons that undergo the stem change are the same.

For example, in the present tense, the je, tu, il, and ils (me, you, he, and they) forms of these kinds of verbs all have a stem change. So once you learn which conjugations need a stem change for one type of stem-changing verb, you will know which conjugations need the stem change for all the other kinds.

-Ayer Verbs

The -ayer verbs have an optional stem change: y changes to i in all forms except for nous (we) and vous (you). For the verb payer (to pay), the conjugations would be:

Subject	Present	Future	Imperfect
je	paie paye	paierai payerai	payais
tu	paies payes	paieras payeras	payais
il	paie paye	paiera payera	payait
nous	payons	paierons payerons	payions
vous	payez	paierez payerez	payiez
ils	paient payent	paieront payeront	payaient

Note that -ayer verb can be conjugated as any regular -er verb, as the second example in each conjugation shows: Either set of conjugations is acceptable.

-Eler and Eter verbs

With -eler and -eter, double the letter "l" or "t" in the stem when conjugating these verbs. An example of an -eter  verb conjugation would be appeler, which means "to call."

Subject	Present	Future	Imperfect
j'	appelle	appellerai	appelais
tu	appelles	appelleras	appelais
il	appelle	appellera	appelait
nous	appelons	appellerons	appelions
vous	appelez	appellerez	appeliez
ils	appellent	appelleront	appelaient

An example of an -eter verb conjugation would be jeter, meaning "to throw."

Subject	Present	Future	Imperfect
je	jette	jetterai	jetais
tu	jettes	jetteras	jetais
il	jette	jettera	jetait
nous	jetons	jetterons	jetions
vous	jetez	jetterez	jetiez
ils	jettent	jetteront	jetaient

The present participle of jeter is formed with an -ant ending to create jetant. It's also an adjective, noun, or gerund in certain circumstances.

-E_er Verbs

For verbs that end in -e_er, where _ indicates one or more consonants, the stem change consists of changing the e before that consonant to è in all forms except for nous and vous. For example, the conjugations of the verb lever (to lift), would be:

Subject	Present	Future	Imperfect
je	lève	lèverai	levais
tu	lèves	lèveras	levais
il	lève	lèvera	levait
nous	lèvons	lèverons	levions
vous	levez	lèverez	leviez
ils	lèvent	lèveront	levaient

Other than acheter (to buy), geler (to freeze), harceler (to harass), and peler (to peel), most verbs that end in -eler and -eter are part of a different stem-change group: -eler or -eter verbs.

-É_er Verbs

All verbs that end in –é_er change the  é to è in the stem-changed conjugations. An example of conjugations for this verb would be compléter, meaning "to complete."

Subject	Present	Future	Imperfect
je	complète	compléterai	complétais
tu	complètes	compléteras	complétais
il	complète	complétera	complétait
nous	complétons	compléterons	complétions
vous	complétez	compléterez	complétiez
ils	complètent	complèteront	complétaie

The present participle of compléter is complétant. This can be used as a verb but also serves as an adjective, gerund, or noun in some circumstances. 

-Oyer and Uyer Verbs

French verbs that end in -oyer and -uyer must change y to i in all forms but nous and vous. For -oyer  verbs, an example would be netoyer,  which means "to clean."

Present	Present	Future	Imperfect
je	nettoie	nettoierai	nettoyais
tu	nettoies	nettoieras	nettoyais
il	nettoie	nettoiera	nettoyait
nous	nettoyons	nettoierons	nettoyions
vous	nettoyez	nettoierez	nettoyiez
ils	nettoient	nettoieront	nettoyaient

For -uyer verbs, an example would be  enoyer, which means "to bore."

Subject	Present	Future	Imperfect
j'	ennuie	ennuierai	ennuyais
tu	ennuies	ennuieras	ennuyais
il	ennuie	ennuiera	ennuyait
nous	ennuyons	ennuierons	ennuyions
vous	ennuyez	ennuierez	ennuyiez
ils	ennuient	ennuieront	ennuyaient

The imperative verb form  is used for short statements that often request or demand something. When using these, skip the subject pronoun: use "ennuie" rather than "tu ennuie."