Present Subjunctive Irregular

Regular subjunctive formation is straightforward — drop the -o from the yo indicative form and add opposite endings. But what about verbs that don't follow this pattern? In this lesson, we cover stem-changing verbs, verbs with irregular yo forms, and the handful of verbs that are truly irregular in the subjunctive.

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Category 1: Stem-Changing Verbs

Many Spanish verbs have a stem change in the present indicative (e → ie, o → ue, e → i). These same stem changes carry over into the subjunctive, with one important difference.

-AR and -ER Stem-Changing Verbs

For -AR and -ER stem-changing verbs, the stem change occurs in all forms except nosotros and vosotros — exactly as in the indicative:

PENSAR (e → ie) — to think

Person	Subjunctive
yo	piense
tú	pienses
él/ella/usted	piense
nosotros/as	pensemos
vosotros/as	penséis
ellos/ellas/ustedes	piensen

VOLVER (o → ue) — to return

Person	Subjunctive
yo	vuelva
tú	vuelvas
él/ella/usted	vuelva
nosotros/as	volvamos
vosotros/as	volváis
ellos/ellas/ustedes	vuelvan

PODER (o → ue) — to be able to

Person	Subjunctive
yo	pueda
tú	puedas
él/ella/usted	pueda
nosotros/as	podamos
vosotros/as	podáis
ellos/ellas/ustedes	puedan

Pattern: The "boot shape" — stem changes happen in all forms except nosotros and vosotros, forming a boot shape in a conjugation grid.

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-IR Stem-Changing Verbs

-IR stem-changing verbs are special. They have the expected stem change in the boot plus an additional change in the nosotros and vosotros forms:

Indicative change	Nosotros/vosotros subjunctive change
e → ie	e → i
e → i	e → i
o → ue	o → u

SENTIR (e → ie, e → i) — to feel

Person	Subjunctive
yo	sienta
tú	sientas
él/ella/usted	sienta
nosotros/as	sintamos
vosotros/as	sintáis
ellos/ellas/ustedes	sientan

PEDIR (e → i, e → i) — to ask for

Person	Subjunctive
yo	pida
tú	pidas
él/ella/usted	pida
nosotros/as	pidamos
vosotros/as	pidáis
ellos/ellas/ustedes	pidan

DORMIR (o → ue, o → u) — to sleep

Person	Subjunctive
yo	duerma
tú	duermas
él/ella/usted	duerma
nosotros/as	durmamos
vosotros/as	durmáis
ellos/ellas/ustedes	duerman

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Category 2: Irregular Yo Forms

These verbs have an irregular yo form in the present indicative. Since the subjunctive is built from the yo form, the "irregularity" flows through to all subjunctive forms. But the endings are perfectly regular!

Key Verbs with Irregular Yo Forms

Infinitive	Yo Indicative	Subjunctive Stem	Subjunctive (yo)
tener (to have)	tengo	teng-	tenga
venir (to come)	vengo	veng-	venga
decir (to say)	digo	dig-	diga
hacer (to do/make)	hago	hag-	haga
poner (to put)	pongo	pong-	ponga
salir (to leave)	salgo	salg-	salta → salga
traer (to bring)	traigo	traig-	traiga
oír (to hear)	oigo	oig-	oiga
conocer (to know)	conozco	conozc-	conozca
producir (to produce)	produzco	produzc-	produzca
caer (to fall)	caigo	caig-	caiga

Full Table: TENER