Stem Changing Verbs in Spanish: Explained For Beginners

Stem-changing verbs in Spanish are a little easier to learn once you spot the pattern behind them. Instead of keeping the same stem when they’re conjugated, these verbs change one of their vowels in certain forms of the present tense.  

That might sound like another rule to memorize, but there’s some good news: stem-changing verbs tend to follow a handful of predictable patterns. Once you know what to look for, “querer” (to love/to want) becomes “quiero” (I love), “poder” (to be able to) becomes “puedo” (I can), and “pedir” (to ask for) becomes “pido” (I ask for) without feeling quite so random.

In this guide, we’ll break down the five stem-changing patterns in Spanish, look at the most common verbs that follow each one, and see how they work in real sentences. First, though, let’s take a quick look at what a verb stem actually is.

What Is The Stem of a Spanish Verb?

The stem is the part of a verb that remains after removing its infinitive ending: -ar, -er, or -ir.

Let’s see some examples:

Verb	Infinitive	Stem	Ending
to cook	cocinar	cocin-	-ar
to drink	beber	beb-	-er
to live	vivir	viv-	-ir

 

Regular verbs keep this stem intact when they’re conjugated. Stem-changing verbs are different: the stem itself changes in certain conjugated forms.

To see what makes stem-changing verbs different, it helps to have the regular pattern fresh in mind. In the present tense, we remove -ar, -er, or -ir from the infinitive and add the appropriate ending.

Ending -ar

Pronoun	Stem	Ending	Full word
Yo	cocin-	-o	cocino
Tú	cocin-	-as	cocinas
Él, ella, usted	cocin-	-a	cocina
Nosotros(as)	cocin-	-amos	cocinamos
Ellos(as), ustedes	cocin-	-an	cocinan

Ending -er

Pronoun	Stem	Ending	Full word
Yo	beb-	-o	bebo
Tú	beb-	-es	bebes
Él, ella, usted	beb-	-e	bebe
Nosotros(as)	beb-	-emos	bebemos
Ellos(as), ustedes	beb-	-en	beben

Ending -ir

Pronoun	Stem	Ending	Full word
Yo	part-	-o	parto
Tú	part-	-es	partes
Él, ella, usted	part-	-e	parte
Nosotros(as)	part-	-imos	partimos
Ellos(as), ustedes	part-	-en	parten

Notice that the stem stays exactly the same in every form. That’s the key difference we’ll see with stem-changing verbs: the ending still follows the usual conjugation pattern, but part of the stem changes.

If you’re not sure how to conjugate verbs in the simple present tense, then check out our post on that topic here.

For now, we are going to examine verbs that don’t follow the regular pattern or structure, i.e. “Stem Changing Verbs”, or “Verbos Radicales” in Spanish.

What is a Stem Changing Verb?

A stem-changing verb is a Spanish verb whose stem changes when it is conjugated in certain forms. In the present tense, this usually means that one vowel in the stem changes while the regular verb ending remains in place.

For example:

• To want: Querer – Quiero (I want)
  (e becomes ie)
• To dream: Soñar – Sueño  (I dream)
  (o becomes ue)
• To repeat: Repetir – Repito (I repeat)
  (e becomes i)

So although these verbs don’t follow the completely regular pattern, the changes aren’t random. Spanish stem-changing verbs fall into several recurring patterns.

What Are The Five Types of Stem-Changing Verbs In Spanish?

In the present tense, Spanish stem-changing verbs generally fall into five patterns:

1. Stem Changing Verbs: E to IE change.
2. Stem Changing Verbs: O to UE change.
3. Stem Changing Verbs: E to I change.
4. Stem Changing Verbs: U to UE change.
5. Stem Changing Verbs: I to IE change.

The first three are by far the most common. The last two are much smaller groups, with u → ue with examples like “jugar” (to play),  and i → ie for verbs like “adquirir” (to acquire) and “inquirir” (to inquire). We’ll dig deeper into these later!

How to Conjugate Stem-Changing Verbs in Spanish

Before continuing, we should clarify an important rule.

For most stem-changing verbs in the present tense, the change occurs in the yo, tú, él/ella/usted, and ellos/ellas/ustedes forms. The nosotros/nosotras and vosotros/vosotras forms normally keep the original stem.

For example, with the verb “pensar” (to think) it changes from e to ie:

	Singular	Plural
Yo	Pienso
Tú	Piensas
Él/ella/usted	Piensa
Nosotros		Pensamos
Vosotros (Spain)		Pensáis
Ellos/ellas/ustedes		Piensan

This will become clearer as we look at the below list of the stem-changing verbs in Spanish.

1. Stem Changing Verbs: E to IE change

In this pattern, an e in the stem changes to ie in the affected forms.

It is worth mentioning that this change affects the largest number of verbs, so it is worth memorizing this rule as soon as possible.

Let’s see a few examples:

Verb	Stem with E infinitive form	Stem with IE when conjugated
To want	querer	Yo quiero
To close	cerrar	Yo cierro
To lie	mentir	Yo miento

Some other verbs that follow this pattern are:

-ER ending	to go up, to ascend	ascender	Yo asciendo
	to understand	entender	Tú entiendes
	to lose	perder	Él pierde
	to want, to love	querer	Ella quiere
	to turn on, to light	encender	Ellos encienden
-AR ending	to close	cerrar	Yo cierro
	to be right, to hit the target	acertar	Tú aciertas
	to think	pensar	ÉL piensa
	to begin	comenzar	Ella comienza
	to start	empezar	Ellos empiezan
-IR ending	to lie	mentir	yo miento
	to suggest	sugerir	tú sugieres
	to prefer	preferir	él prefiere
	to feel	sentir	ella siente
	to warn	advertir	ellos advierten

Examples:

• The kids do not understand this exercise – Los niños no entienden este ejercicio.
• Anna thinks a lot about her future – Anna piensa mucho en su futuro.
• Why do you always lie? – ¿Por qué siempre mientes?

The verb ending doesn’t change because of the stem change. The important thing is what happens inside the stem.

2. Stem Changing Verbs: O to UE change

With this pattern, an o in the stem changes to ue in the affected present-tense forms,  just like in the following example:

Verb	Stem with O infinitive form	Stem with UE when conjugated
to be able to	poder	puedo
to count	contar	cuento
to die	morir	muero

Some verbs that follow this pattern are:

-ER ending	to move	mover	Yo muevo
	to resolve	resolver	Tú resuelves
	to be accustomed to	soler	Él suele
	to rain	llover	Llueve
	to return	volver	Ellos vuelven
-AR ending	to have lunch	almorzar	Yo almuerzo
	to cost	costar	Eso cuesta
	to remember	recordar	Él recuerda
	to dream	soñar	Ella sueña
	to beg	rogar	Ellos ruegan
-IR ending	to sleep	dormir	Yo duermo
	to die	morir	Tú mueres

Note: The verb oler (to smell) follows the o to  ue pattern but it also adds an h at the beginning. The nosotros form, however, remains regular: olemos.

Let’s take a look:

English	Conjugation Present tense
I smell	Yo huelo
You smell	Tú hueles
He, she smells, you (formal) smell	Él, ella, usted huele
We smell	Nosotros(as) olemos
They smell, you (plural) smell	Ellos, ellas, ustedes huelen

Examples

• Do not move the chair, please – No muevas la silla, por favor.
• I often have lunch with my workmates – A menudo almuerzo con mis compañeros de trabajo.
• Karina sleeps late on weekends – Karina duerme hasta tarde los fines de semana.

3. Stem Changing Verbs: E to I change

This pattern changes e → i and is found only among -ir verbs in the present tense.For example: verbs ending with -edir (e.g. pedir, impedir), -egir (e.g. elegir, corregir, regir), -eguir (e.g conseguir, perseguir, seguir) and -eñir (e.g. ceñir, reñir).

Verb	Stem with E infinitive form	Stem with I when conjugated
To measure	medir	mido

Some verbs that follow this pattern are:

-IR ending	to obtain	conseguir	Yo consigo
	to ask for	pedir	Tú pides
	to choose, to elect	elegir	Él elige
	to chase, to run after	perseguir	Ella persigue
	to serve, to be useful	servir	Ellos sirven
	to follow	seguir	Yo sigo
	to correct	corregir	Tú corriges
	to prevent, to stop, to block	impedir	Él impide
	to say	decir	Ella dice
	to laugh	reír	Ellos ríen
	to fight, to row	reñir	yo riño
	to gird, to fasten	ceñir	tú ciñes
	to govern, to rule	regir	Él rige

 

Examples

• Choose what you want! – ¡Elige lo que quieras!
• Javier follows Nicki Minaj on Instagram – Javier sigue a Nicki Minaj en Instagram.
• The teacher corrects math exams – El profesor corrige los exámenes de matemáticas.

4. Stem Changing Verbs: U to UE change

This is maybe the easiest rule inside of the group of radicals as there is only one verb that follows this pattern: jugar (to play). With this verb, we just substitute the letter u in its stem to ue in all pronouns (except nosotros).

Piece of cake, right?

Verb	Stem with U infinite verb	Stem with UE when conjugated
To play	jugar	juego

Examples

• Some kids play in the playground – Algunos niños juegan en el patio.
• I play UNO with my friends whenever I can – Siempre que puedo juego UNO con mis amigos.
• Do you play poker? – ¿Juegas póquer?

5. Stem Changing Verbs: I to IE change

This final pattern is only followed by two verbs: adquirir (to buy, to acquire) and inquirir (to inquire, to question). The rule is quite simple: drop the i in the stem and replace it with ie when conjugating.

Verb	Stem with I	Stem with IE
To buy, to acquire	adquirir	Yo adquiero
To inquire, to question	inquirir	Yo inquiero

Examples

• The district attorney inquires about the motives of the accused – La fiscal inquiere sobre los motivos del acusado.
• If you acquire more knowledge, you will strengthen your intellect – Si adquieres más conocimiento, fortalecerás tu intelecto.

Stem Changing Verbs in Spanish: Practice

Test yourself with these 10 sentences! 

Fill in the blank with the correct stem-changed form of the verb in parentheses:

1. Matt no ________ (entender) los ejercicios del Subjuntivo.
2. La bailarina ________ (mover) los pies al son de la salsa.
3. Carlos y su hermanito ________ (repetir) la canción una y otra vez.
4. Yo ________ (jugar) baloncesto de vez en cuando con algunos amigos.
5. Helen y su marido ________ (adquirir) una nueva casa esta tarde. ¡Qué emoción!
6. ¿(Tú) ________ (preferir) ir a la montaña o la playa?
7. El águila es un ave que ________ (volar) a grandes alturas.
8. Esas personas ________ (decir) cosas sin sentido.
9. (Yo) ________ (querer) boletos para el concierto, pero no tengo suficiente dinero.
10. Ellas ________ (soler) cenar junto a sus vecinos cada domingo.

Answers

1. Matt no entiende los ejercicios del Subjuntivo.
2. La bailarina mueve los pies al son de la salsa.
3. Carlos y su hermanito repiten la canción una y otra vez.
4. Yo juego baloncesto de vez en cuando con algunos amigos.
5. Helen y su marido adquieren una nueva casa esta tarde. ¡Qué emoción!
6. ¿(Tú) Prefieres ir a la montaña o la playa?
7. El águila es un ave que vuela a grandes alturas.
8. Esas personas dicen cosas sin sentido.
9. (Yo) Quiero boletos para el concierto, pero no tengo suficiente dinero.
10. Ellas suelen cenar junto a sus vecinos cada domingo.