Navigating through Spanish conjugations can be quite perplexing, especially considering the myriad of endings to memorize. What complicates matters further is the presence of spelling alterations in some verbs. Stem-changing verbs, ubiquitous in Spanish, add another layer of complexity.

However, the upside is that mastering them isn’t as daunting as it may seem.

Given the significance of this subject, this article will comprehensively cover all the vital aspects of Spanish stem-changing verbs. Here’s what we’ll delve into:

Understanding Stem-Changing Verbs in Spanish

Stem-changing verbs in Spanish, as implied by their name, are verbs where the root undergoes spelling alterations.
These changes serve two primary purposes:

1. Facilitating pronunciation.
2. Maintaining consistency with the pronunciation of the infinitive verb.

Refer to the graphic above. If we were to conjugate “dormir” without adhering to its spelling alterations, the pronunciation would become less straightforward, potentially causing tongue-twisting situations. Note that these stem-changing rules do not apply to the “nosotros” and “vosotros” forms.

Most of the spelling changes encountered in Spanish stem-changing verbs involve vowels. Specifically, one or two vowels are substituted for a vowel in the stem. The most prevalent alterations are:

• e → ie
• e → i
• o → ue
• u → ue

These adjustments are primarily seen in the present tense. However, certain verbs conjugated in the preterite tense also exhibit stem changes.

In the following sections, you’ll find charts outlining the necessary modifications and lists of common verbs that adhere to these patterns.

Stem-Changing Verbs in the Present Tense of Spanish

The majority of stem-changing verbs in Spanish exhibit their changes in the present tense conjugations. It’s worth noting that these alterations do not affect the nosotros and vosotros forms.

Kindly observe: Stem-changing verbs in Spanish impact the verb’s stem, not its conjugation. Therefore, after applying the spelling change, you continue to use the corresponding endings for -AR, -ER, and -IR verbs.

The stem changes in the present tense include:

E > IE

The most common stem-changing verbs in Spanish, where ‘-e’ changes to ‘-ie’, are:

• Querer – To want
• Despertar – To wake up
• Cerrar – To close
• Empezar – To begin 
• Comenzar – To begin
• Pensar – To think
• Sentar – To sit
• Convertir – To convert / To transform
• Divertir – To have fun / To amuse
• Preferir – To prefer
• Mentir – To lie
• Encender – To turn on / to ignite
• Tener* – To have 
• Encerrar – To lock up
  _{*In the present tense, “tener” has an irregular conjugation for ‘yo’ (tengo). For the rest of the subjects, it remains an ‘e’ to ‘ie’ stem-changing verb.}

Let’s take “pensar” as an example to illustrate a conjugation chart. Remember to use the appropriate endings for each type of verb (-AR, -ER, -IR).

Keeping this conjugation pattern in mind, here are a few examples of stem-changing verbs in the present tense:

Ella prefiere escuchar música.
She prefers to listen to music.

¿Quieres ir al cine?
Do you want to go to the movies?

Samuel se sienta en la esquina.
Samuel sits in the corner.

Ellos tienen dos perros.
They have two dogs.

Nosotros no tenemos mascotas.
We don’t have pets.

Kindly observe: Stem changes also apply to Spanish reflexive verbs.

E > I

Examples of stem-changing verbs from “e” to “i” include:

• Pedir – To ask / To order
• Medir – To measure / To be
• Seguir – To follow
• Vestir – To dress 
• Servir – To work / To serve
• Repetir – To repeat 

Here’s an example of conjugating this type of stem-changing verb:

Ben siempre pide el mismo pastel.
Ben always orders the same cake.

Ellas miden lo mismo que yo.
They’re the same height as me.

Mis perros me siguen a todos lados.
My dogs follow me everywhere.

Tú te vistes muy bien.
You dress very well.

Kindly observe: Numerous Spanish verbs serve as suffixes to create other verbs. For instance, “pedir” is found in the verb “despedir,” and “seguir” is within “perseguir.” Given that their suffix is a stem-changing verb, these verbs will also exhibit the same spelling alterations.

Lucas nunca se despide.
Lucas never says goodbye.

Mi primito persigue a mi gato.
My little cousin chases my cat.

O > UE

Common verbs that undergo this type of stem change include:

• Dormir – To sleep
• Volver – To come back
• Morir – To die
• Acordar – To remember 
• Recordar – To remember 
• Costar – To cost
• Almorzar – To have lunch
• Contar – To count
• Probar – To taste / To try on
• Doler – To hurt
• Llover – To rain
• Morder – To bite 
• Poder – Can
• Encontrar – To find
• Soñar – To dream
• Demostrar – To show
• Avergonzar – To embarrass 

Here is a chart illustrating the spelling changes from ‘o’ to ‘ue’:

And here are a few examples with different verbs:

En México, llueve mucho.
It rains a lot in Mexico.

Emma sueña con vivir en Francia.
Emma dreams of living in France.

La verdad no me acuerdo.
I don’t remember to be honest.

Creo que ellas pueden ayudarte.
I think they can help you.

No encontramos el control.
We can’t find the remote.

Kindly observe: You might have noticed a pattern where the vowel we change in stem-changing verbs is the last vowel right before the infinitive ending. Do you want to double-check? Go back to the verb lists and examine the vowels that I’ve bolded for you.

U > UE

This type of spelling change is only applied to the verb jugar. In this case, you must replace the ‘u‘ with the vowels ‘ue‘.

Yo juego con mi hermanito.
I play with my little brother.

Los niños juegan en el parque.
The kids play in the park.

Marcus juega fútbol todos los días.
Marcus plays soccer every day.

Stem-Changing Verbs in the Preterite Tense

Stem-changing -IR verbs in the present tense exhibit spelling changes in the preterite tense as well. However, these alterations are only observed in the third person singular and plural forms (él and ellos).

Here are some examples of stem-changing verbs in the preterite tense:

E → I

• Seguir
• Pedir
• Medir
• Vestir
• Despedir
• Convertir 
• Preferir
• Mentir
• Divertir

Maggie nos mintió.
Maggie lied to us.

Yo no te mentí.
I didn’t lie to you.

¿Quién te vistió?
Who dressed you up?

Ellos prefirieron ir al cine.
They preferred going to the movies.

O → U

• Dormir
• Morir

Bonus: Consonant Alterations in Spanish Verbs

In addition to the stem-changing verbs in Spanish, there are other verbs that undergo consonant alterations. These alterations typically involve replacing one consonant with another to maintain consistent pronunciation.

These changes usually occur in the first person singular (yo) form and may affect either the present or preterite conjugation of the verb.

Here are some examples of verbs with consonant changes in the preterite tense:

-gar to gu:

• Apagar – To turn off
• Pagar – To pay
• Llegar – To arrive
• Alegrar – To cheer / To make happy
• Cargar – To carry
• Castigar – To punish
• Colgar – To hung up
• Jugar – To play
• Obligar – To force
• Pegar – To glue / To hit

-glar to ‘glu’ 

• Arreglar – To fix

-zar to c: 

• Almorzar – To have lunch
• Amenazar – To threaten 
• Empezar – To begin 

-car to qu:

• Buscar – To look for
• Sacar – To take out
• Chocar – To crash
• Tocar – To touch
• Atacar – To attack
• Equivocar – To make a mistake
• Marcar – To mark / To call
• Rascar – To scratch 
• Secar – To dry
• Explicar – To explain 

Verbs with spelling changes in the present

-cer to zc 

• Conocer – To know
• Agradecer – To say thank you
• Aparecer – To appear
• Convencer – To convince
• Crecer – To grow
• Desaparecer – To disappear 
• Merecer – To deserve
• Obedecer – To obey
• Parecer – To seem 

No la conozco.
I don’t know her.

Ella conoce a Marcos.
She knows Marcos.

Yo apagué la luz.
I turned the light off.

¿Por qué apagaste la tele?
Why did you turn the TV off?

Me merezco ese ascenso.
I deserve that promotion.

Tú te mereces ese trabajo.
You deserve that job.

Te busqué por todos lados.
I looked for you everywhere.

Mis primos buscaron a su perro por días.
My cousins looked for their dog for days.

Distinguishing Between Spanish Stem-Changing Verbs and Irregular Verbs

Many Spanish learners mistakenly classify stem-changing verbs as irregular verbs. However, there’s a clear distinction between the two. Stem-changing verbs and irregular verbs in Spanish differ significantly, and I’ll clarify this difference for you.

Stem-changing verbs undergo minor spelling adjustments in their stems to maintain pronunciation, and they adhere to the conjugation patterns of regular verbs. In contrast, irregular verbs undergo major spelling alterations in their stems and may employ different conjugation endings compared to regular verbs.

In essence, the modifications required for stem-changing verbs are minimal. Once completed, they closely resemble their infinitive forms and follow the same conjugation patterns as regular verbs. Irregular verbs, however, undergo substantial transformations, leading to notable differences in their conjugation forms.

Absolutely! Take a regular verb like ‘comer’ for instance; it’s straightforward. Adjust the verb’s ending according to the subject and tense. Now, with a stem-changing verb like ‘querer’, it follows the same regular endings, much like ‘comer’. But when we examine the conjugations for an irregular verb like ‘ser’, it’s a whole different story. Without prior memorization, you might not even recognize its conjugated forms as related to the infinitive verb.

Essential Considerations Regarding Stem-Changing Verbs in Spanish

A significant portion of frequently used Spanish verbs undergo stem-changing patterns, making it vital to grasp this concept. Here are key points to bear in mind:

• Spanish employs spelling adjustments to maintain consistent pronunciation.
• Stem-changing verbs do not affect nosotros and vosotros forms.
• The bulk of stem-changing verbs in Spanish occur in the present tense.
• These spelling modifications entail substituting one vowel for another (or multiple).
• Stem-changing verbs come in four categories:
  
  • From ‘e’ to ‘ie’.
  • From ‘e’ to ‘i’.
  • From ‘o’ to ‘ue’.
  • From ‘u’ to ‘ue’.

• -IR verbs with vocalic spelling changes in the present tense also exhibit stem-changing behavior in the preterite tense.
• Stem-changing verbs in the preterite tense only impact the third person (singular and plural).
• Spelling adjustments in the preterite tense involve:
  
  • From ‘e’ to ‘i’.
  • From ‘o’ to ‘u’.

• Certain Spanish verbs undergo consonant changes, but these apply solely to the first person singular (yo).
• While commonly confused, stem-changing verbs and irregular verbs are different.
  • As the name suggests, stem-changing verbs have the same endings as regular verbs and only experience minor spelling changes to their stems.
  • In contrast, irregular verbs undergo substantial alterations to both stems and endings.