stem changers in spanish

Part II: How to Conjugate Stem-Changers in Spanish

How to Conjugate Spanish Verbs - stem changers

Struggling with Spanish grammar? As you’re learning how to conjugate verbs in Spanish, you’ll need to watch out for stem-changers! Here’s an overview from Fairfax, CA tutor Jason N...


If you’re reading this now, it probably means you are well-aware of the importance of conjugation to use verbs to describe situations and events. And as you’re learning a new language, like Spanish, this is essential to your progress!

Conjugations enable us to form coherent sentences that specify the ‘who’ and ‘what’ of a particular action. This article is part II of a series of blog posts where I’ll explain how to conjugate Spanish verbs — so if you haven’t read that first one yet, do so now.

If you have already read the first article, great! Now that you know about to conjugate basic verbs in present tense, next I’ll show you how to take your conjugation skills to the next level. This involves learning stem-changing verbs in Spanish.

In all three conjugations of verbs (with –ar, –er, or –ir endings) there are some verbs whose vowels change within the stem. Let’s go through some key vocabulary first.

  • The word ‘infinitive‘ refers to the verb before it’s conjugated.
  • The ‘stem‘ of a verb usually refers to the first syllable of the verb in its infinitive form.
  • Consequently, a ‘stem-changing verb‘ is when the stem changes from its infinitive to its conjugated form.

The beginning three steps are the same as with the normal verbs:

How to Conjugate Spanish Verbs

To understand stem-changer conjugations, we want to focus here on the stem’s vowel. These stem-changes occur in all of the five conjugation variants except nosotros or ‘we’ form (and vosotros if you’re in Spain), which both maintain their regular stem.

There are six types of stem-changers in Spanish:
e → i
o → ue
e  → ie
i → ie
u → ue*
o → hue

*Note: We only implement the stem-change (u → ue) in the verb jugar (to play) as most verbs with a ‘u’ in their stem aren’t stem-changers.

How to Conjugate e → i Stem-Changers in Spanish

Let’s go through the most common three. In this example, the stem of the verb pedir (to ask for) is ped-. The key vowel here is the ‘e.’ The ‘e’ changes to an ‘i’ when it’s conjugated in the present tense, except for in its nosotros form.

Pedir (e → i)
Yo Pido

Tú Pides
Él/ella/usted Pide
Nosotros Pedimos
Ellos/ellas/ustedes Piden

As you can see, the ‘e’ in the stem ped- changes to an ‘i’ in all the five person variants besides nosotros. Not too difficult, right?

How to Conjugate o → ue Stem-Changers in Spanish

Let’s try another common one. Just like the ‘e’ in pedir changes to an ‘i,’ the ‘o’ in poder, from the stem pod- changes to ‘ue,’ except, as always, in its nosotros form.

Poder (o → ue)

How to Conjugate e → ie Stem-Changers in Spanish

Another frequent stem-changer is the ‘i’ to ‘ie.’ Let’s take, for example, querer:

Querer (e → ie)

Let’s practice with the following verbs:

Medir (e → i) To measure
Colgar (o → ue) To hang up
Cerrar (e → ie) To close

Spanish Conjugation Chart - Stem-Changers

Aside from stem-changing verbs, many present-tense verbs have an irregular conjugation in their Yo form, in that it doesn’t follow basic tendency to end in ‘o’ at the end of the word after removing the ending (-ar, –ir or –er), and instead ends in –go.

For example, hacer (to do or to make) in its Yo present form: o → go

Instead of conjugating hacer in its Yo form as “haco,” we say, “hago” to mean, “I do or make.” This is the same with venir and seguir.

Spanish Verb Conjugation Practice — Stem-Changers

Now, practice with the following verbs in their ‘yo’ form:

Spanish Conjugation Chart - Stem-Changers

Not sure if you’ve quite got it? A Spanish tutor can help you flesh this out. Stay tuned for Part III when I show you about to conjugate verbs in their past tense.

Jason N width=Post Author: Jason N.
Jason N. tutors in English and Spanish in Fairfax, CA. He majored in Spanish at UC Davis, lived in Mexico for 3 years where he completed a Master’s degree in Counseling, and studied Spanish Literature and Psychology at the University of Costa Rica. Learn more about Jason here! 

Photo by Matt-Richards

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