Resources for further reading:
Irregular Verbs that End in –zar, -car, -gar
Verbs that end with -zar, -car, or –gar cannot be conjugated normally in the “yo” form of the preterite tense without having to change their spelling of necessity to preserve the pronunciation.
For example, think of the verb pescar (to fish). Try to conjugate it normally in the “yo” form: pesc + -é = pescé. The letter ‘c’ is a soft sound in Spanish, so the word would sound like pesé. In order to preserve the hard ‘k’ sound of “pescar,” Spanish changes the ‘c’ to a ‘qu,’ making the ‘yo’ form into pesqué.
The following table gives examples of some irregular verbs that change in the “yo” form to preserve the correct pronunciation. Note that the other conjugations remain regular.
| Subject Pronoun | COMENZAR - to start | PESCAR - to fish | PAGAR - to pay |
|---|---|---|---|
| Yo | comencé | pesqué | pagué |
| Tú | comenzaste | pescaste | pagaste |
| Ud., él, ella, | comenzó | pescó | pagó |
| nosotros/as | comenzamos | pescamos | pagamos |
| vosotros/as | comenzasteis | pescasteis | pagasteis |
| Uds., ellos, ellas | comenzaron | pescaron | pagaron |
Other verbs that change in this way include jugar (jugué) and buscar (busqué).
Por ejemplo (for example):


Practice Your Pronunciation With Rocket Record
Stem-Changing Verbs in the Past
Do you remember what a stem change is? A stem change is when the stem of a verb (the part that is left when the –AR, -ER, or –IR ending is taken away) changes its vowel sounds from –e to –ie, –e to –i, –o to –ue, or –o to –u.
To understand stem changes in the preterite tense, you must first note that:
- All the —AR and —ER verbs that stem change in the present (such as mostrar, almorzar, pensar, perder, tener, and entender) do NOT stem change in the preterite.
(These verbs may be irregular in other ways, however.)
In the "Spanish Present Progressive" lesson in the Beginner’s section, you learned about stem changes in present participles, such as estoy viniendo, estoy durmiendo, and estoy diciendo.
- The –IR stem-changing verbs WILL stem change in the preterite, but only in the third person singular and plural. They follow the same rules as the present participles, except that all –o to –ue stem changers become –o to –u, and all –e to –ie stem changers become –e to –i.
(You may feel a bit discouraged to know that these verbs may have additional irregularities, such as the verbs venir and decir, which you’ll study later on.)
All these rules may sound a bit confusing, so here are some examples.
| Subject pronoun | —o to —u | —o to —u |
|---|---|---|
| REPETIR - to repeat | DORMIR - to sleep | |
| Yo | repetí | dormí |
| Tú | repetiste | dormiste |
| Ud., él, ella | repitió | durmió |
| nosotros/as | repetimos | ormimos |
| vosotros/as | repetisteis | dormisteis |
| Uds., ellos, ellas | repitieron | durmieron |
Other –e to –i verbs include servir, sentir, preferir, and pedir.
Other –o to –u verbs include morir.
Por ejemplo:

Want to learn more about Spanish Tenses? Take a look at these lessons:
- Found out how to use the present progressive tense in Spanish here.
- The irregularities in the future tense in Spanish
- Learn about the Spanish past progressive tense
See you soon! ¡Hasta pronto!
Mauricio Evlampieff: Rocket Spanish