Stem Changing Verbs in Spanish for Beginners

Stem changing verbs in Spanish are irregular verbs that have a slight change in their root when conjugated. 

Because of their unpredictability, irregular verbs have a kind of bad reputation. However, in reality, all you have to do is to understand how these verbs actually behave and include this information in your Spanish knowledge. 

In this post, I’ll explain what stem changing verbs in Spanish are, when you have to apply the stem changes, and how many types of this type of verbs are. Then I’ll discuss in detail each one of the different cases, give you a full conjugation set in present tense, and include a list of stem changing verbs in Spanish for every type. 

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What Are Stem Changing Verbs?

In Spanish, every verb in infinitive is formed by the root of the verb or “stem,” and one of three endings: -ar, -er, or -ir. For instance, let’s see how this work with the verb comer or “to eat”:

Stem: com-

Ending: -er

When conjugating regular verbs, all you have to do is to take the stem, in this case com-, and follow the regular pattern of conjugation for verbs ending in -er.

Let’s see how that goes in the present tense:

Notice how the stem doesn’t change. Well, as their name suggests, when you conjugate stem changing verbs in Spanish, the stem does change.

When You Should Change the Stem

Before getting into how to conjugate stem changing verbs in Spanish, it’s important to mention that these verbs only change their stem when conjugated in three forms: 

• present tense
• preterite
• present progressive

And they don’t necessarily change their stem in all three tenses. Some might change in the present, while others do it in preterite. Take for example the verb pensar or “to think.” 

Present Tense:

Yo pienso
I think

Preterite:

Yo pensé 
I thought

Notice how the stem changed in present tense to piens-, while it stayed the same in preterite pens-.

That’s why they’re called irregular verbs. They just don’t like following an established pattern, and behave in capricious ways. 

At first, you’ll have to think about when to change the stem, but as you continue progressing in your Spanish learning process, the conjugation of stem changing verbs in Spanish will come to you naturally. 

Types of Stem Changing Verbs in Spanish

There are five ways that a stem may change in stem changing verbs in Spanish:

• e to i
• e to ie
• o to ue
• i to ie
• u to ue

Let’s see how each one of them works. 

e to i

This case applies for some irregular verbs ending in -ir. You have to take the e in the last syllable of the stem, and change it to i. 

Example Verb: pedir (to ask), present tense

Notice how the stem changes in all forms except the first-person plural nosotros. This is normal with stem-changing verbs in Spanish. The fact that they change their stem most times doesn’t mean that they have to do it all the time. 

Here’s another example to illustrate this better.

Example Verb: repetir (to repeat), present tense

As you can see, the same thing happens. The present tense stem changes do not apply to nosotros. This also applies for the second person plural informal: vosotros. I don’t include this person here because nobody uses it anymore in Latin America. 

Some stem changing verbs in Spanish may also be irregular verbs in the yo form. Besides their changing stem, they also add another variation in the yo form. For example elegir – yo elijo (I choose), or decir – yo digo (I say).

Common e to i stem changing verbs: 

conseguir – to obtain

decir – to say

pedir – to ask

elegir – to choose

servir – to serve

repetir – to repeat

seguir – to follow

medir – to measure

despedir – to say goodbye

corregir – to correct

e to ie

This is the most common of the stem changes as it affects verbs with the three different infinitive endings, -ar, -er, and -ir. In this case, you have to change the e in the last syllable of the stem to ie. 

Example Verb: pensar (to think), present tense

Common e to ie stem changing verbs: 

cerrar – to close

defender – to defend

empezar – to begin

mentir – to lie

sentir – to feel

entender – to understand

tener – to have

calentar – to warm

negar – to deny

perder – to lose

venir – to come

Consider that some verbs on this list such as tener and venir, are also irregular yo form verbs, and for that reason the stem change doesn’t apply: 

Yo tengo – I have

Yo vengo – I come

o to ue

This one is also a common stem change affecting verbs with the three infinitive endings. In this case, you have to change the o in the last syllable of the stem to ue. 

Example Verb: mover (to move), present tense

Common o to ue stem changing verbs: 

costar – to cost

contar – to count

dormir – to sleep

probar – to prove, to taste

recordar – to remember

resolver – to resolve

mostrar – to show

volar – to fly

soñar – to dream

poder – to can, to be able to

morir – to die

rogar – to beg

encontrar – to find

morder – to bite

i to ie

Just two stem changing verbs in Spanish apply to this change: adquirir (to acquire) and inquirir (to inquire). You have to add an e after the i in the last syllable of the stem. 

Example Verb: adquirir (to acquire), present tense

u to ue

There’s only one stem changing verb in Spanish that apply to this change: jugar (to play). You have to add an e after the u in the last syllable of the stem. 

Example Verb: jugar (to play), present tense

Practice Your Stem Changing Verbs in Spanish

To master the stem changing verbs in Spanish, you’ll have to study and memorize them at first. Keep at it, and with practice, you’ll get used to the different endings and conjugations. 

Sign up for a free trial class with one of our certified, native Spanish-speaking teachers from Guatemala, and start using stem changing verbs in Spanish today!

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Luis F. Dominguez

Freelance Writer at Homeschool Spanish Academy

Luis F. Domínguez is a freelance writer and independent journalist interested in travel, languages, art, books, history, philosophy, politics and sports. He has written for Fodor’s, Yahoo!, Sports Illustrated, Telemundo, and Villa Experience, among other brands of print and digital media in Europe and North America.

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