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Part 2: The Preterite Tense Guide: Stem-Changing 'u' and 'i' Verbs

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<h1>Stem-Changing Verbs: 'u' and 'i' Verbs</h1>

Hello everyone, and welcome to the second part of my guide to conjugating verbs in the Preterite tense. This time, we will cover a group of stem-changing verbs which I call the 'u' and 'i' verbs, because those are the vowel changes that occur in these verbs. This will be a rather lengthy section, as there is a lot to explain here! To see part one of this guide, see here: https://www.duolingo.com/comment/7322457


First, we need to be familiar with these verbs in the present indicative tense, if we want to learn how to change them to the preterite tense.

Our example verbs:

  • Empezar (to start)
  • Querer (to want, to care about)
  • Pedir (to ask for)
  • Volar (to fly)
  • Dormir (to sleep)
  • Mentir (to lie)
  • Jugar (to play)
  • Volver (to return)

(We will use 'yo' form to conjugate in the present indicative tense)

  • empezar -> empiezo
  • querer -> quiero
  • pedir -> pido
  • volar -> vuelo
  • dormir -> duermo
  • mentir -> miento
  • jugar -> juego
  • volver -> vuelvo

You will notice that the vowels in these verbs change when they are conjugated for 'yo' form in the present indicative tense. This vowel change occurs for all subjects, except for 'nosotros.' So, how do we apply these vowel changes to verbs in the preterite tense?

<h1>In the Preterite Tense</h1>

The way to go from these vowel-changing present indicative verbs to the preterite tense is not too complicated.

  • First, disregard all of the 'ar' and 'er' verbs that have these changes. The vowel changes in these 'ar' and 'er' verbs do not occur in the preterite tense. Only 'ir' verbs keep the vowel changes.
  • Second, only use the third person pronouns: Él/ella/usted, and ellos/ellas/ustedes
  • Third, use the present indicative conjugation, and remove the 'e' from the vowel changes. Example: ella duerme -> ella durme
  • Lastly, apply the regular preterite verb endings to the verb. Example: ella durme -> ella durmió


First, let's take a look at the verbs in this category which actually do still have stem changes in the preterite tense. These are all 'ir' verbs and remove the 'e' sound from the present indicative conjugation. However, only the third person pronouns keep the vowel changes. I will provide the examples by showing the transition from the present indicative tense to the preterite tense.

Example 1: dormir

  • duermo -> dormí
  • duermes -> dormiste
  • duerme -> durmió
  • dormimos -> dormimos
  • duermen -> durmieron

Example 2: mentir

  • miento -> mentí
  • mientes -> mentiste
  • miente -> mintió
  • mentimos -> mentimos
  • mienten -> mintieron

Example 3: pedir

  • pido -> pedí
  • pides -> pediste
  • pide -> pidió
  • pedimos -> pedimos
  • piden -> pidieron

See how the first and second person pronouns use regular conjugations in the preterite tense?

I will also provide some of the 'ar' and 'er' verbs' conjugations, to demonstrate how they are 100% regular in the preterite tense.

Example 4: volar

  • vuelo -> volé
  • vuelas -> volaste
  • vuela -> voló
  • volamos -> volamos
  • vuelan -> volaron

Example 5: volver

  • vuelvo -> volví
  • vuelves -> volviste
  • vuelve -> volvió
  • volvemos -> volvimos
  • vuelven -> volvieron

As you can see, these verbs become regular in the preterite tense. Notice that I did not use empezar, as I covered the one irregularity in it in the previous section about 'car,' 'gar,' and 'zar' verbs. I also did not use querer because it is part of a different group of irregulars which I will explain later.

I hope this helps you guys! Please tell me if I need to make any corrections!

3 years ago



I do not know enough to correct anything but this sure does help me, thanks for your hard work

3 years ago

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volver a + infinitive = expresses the idea of again Los alumnos vuelven de llegar tarde. It would be helpful if you include the English with the Spanish infinitive. Thanks for your hard work.

3 years ago