Spanish Grammar: Verbs

Radical-Changing -ar & -er Verbs

Radical (stem vowel) changing verbs of the first & second conjugations include ar and er verbs.

There are some verbs in which the vowel of the stem changes when it falls under the stress. You have observed already that the expression for I want is quiero, with ie, but the infinitive is querer, with e. You have noticed that I meet is encuentro, with ue, but the infinitive is encontrar. There is a group of verbs which has this type of irregularity and no other, and we call this group radical-changing verbs.

If the vowel of the stem or radical vowel is o it becomes ue under the stress. If the radical vowel is e it becomes ie under the stress. Where the radical vowel does not fall under the stress, there is no change.

We are considering here only the verbs of the first and second conjugations. Of the tenses studied so far, the radical changes occur only in the first, second, third persons singular, and the third person plural of the present tense.

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E to IE stem change

See:	pensar	(to think)
See:	entender	(to understand)

(Note that no change takes place in the first person plural of these verbs because the accent does not fall upon the vowel of the stem but upon the first syllable of the ending.)

Other important verbs conjugated exactly like those above and changing the vowel of the stem from e to ie follow:

See:	cerrar	(to close)
See:	comenzar	(to begin)
See:	despertarse	(to wake up)
See:	empezar	(to begin)
See:	perder	(to lose)
See:	nevar	(to snow)
See:	sentarse	(to seat)

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o to ue stem change

See:	contar	(to count)
See:	volver	(to return)

(Note here again that no change takes place in the first person plural of these verbs because the accent does not fall upon the vowel of the stem but upon the first syllable of the ending.)

Other common verbs conjugated exactly like those above and changing the vowel of the stem from o to ue are as follows:

See:	acordarse	(to remember)
See:	acostarse	(to go to bed)
See:	almorzar	(to eat lunch)
See:	encontrar	(to find)
See:	recordar	(to remember)
See:	mover	(to move)

All vowel changing verbs of the first and second conjugations, studied above, suffer no changes in the past tense (preterite). In the past tense they remain completely regular.

There is one first conjugation verb in which the radical u changes to ue under the stress:

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U to ue stem change

See:

jugar

(to play)

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Radical-Changing -ir Verbs

In the present tense, certain verbs of the third conjugation also change the root of the stem, when stressed, from e to ie and from o to ue. (See the section for similar changes in verbs of the first and second conjugation.) These third conjugations verbs are treated separately here because they also undergo a change in the past tense. As has already been studied, vowel changing verbs of the first and second conjugations remain regular in the past tense.

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E to ie verbs

See:

sentir

(to feel)

These verbs are conjugated exactly like sentir and change the vowel e of their stems to ie whenever the accent falls on this vowel:

See:	preferir	(to prefer)
See:	mentir	(to lie)
See:	divertirse	(to enjoy oneself)

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O to ue verbs

See:

dormir

(to sleep)

These verbs are conjugated exactly like dormir and change the vowel o of their stems to ue whenever the accent falls on this vowel:

See:

morir

(to die)

A special group of verbs of the third conjugation change the vowel e of the stem to i in the present tense, whenever the stress or accent falls upon this vowel. The verb pedir is typical of this group.

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E to I verbs

See:

pedir

(to ask for)

(Note, again, that as in the case of all vowel changing verbs, the first person plural remains regular since the accent does not fall upon the vowel of the stem but, instead, upon the first syllable of the ending.)

These third conjugation verbs are conjugated exactly like pedir and thus change the vowel of their stem from e to i:

See:	repetir	(to repeat)
See:	servir	(to serve)
See:	reírse	(to laugh)
See:	vestirse	(to get dressed)
See:	despedirse	(to say goodbye)

All of the above verbs of the third conjugation which undergo a change in the vowel of their stem in the present tense also have one slight irregularity in the past tense (preterite). In the past tense they change the e of their stem to i or the o of their stem to u in the third person,* singular and plural. I.e., él/ella/Ud and ellos/ellas/Uds.