There are many -ar, -er and -ir stem- changing (sometimes called “radical” [“having to do with the root”]) verbs in Spanish.
In the most common patterns, the e of the stem changes to ie, the o to ue, and the e to i. All of these changes occur only in stressed syllables, in other words, in all persons except nosotros and vosotros. That the stems of these verbs change should not present comprehension problems, provided that you recognize the infinitives.
|pensar (to think)||dormir (to sleep)||pedir (to ask for/request)|
|él, Ella, Ud.||piensa||duerme||pide|
|ellos, ellas, Uds.||piensan||duermen||piden|
One exception to the above pattern is the verb jugar (“to play” [a sport, a game]), which used to have an o in the stem, but made a late shift to a u, which is the vowel that changes to ue.
In the vocabulary lists in this text, stem-changing verbs are indicated by the vowel(s) to which the stem changes, put in parentheses immediately after the infinitive.
almorzar (ue)- to eat lunch
cerrar (ie)- to close, to shut
comenzar (ie)- to begin, to start*
devolver (ue)- to return (an object)
dormir (ue)- to sleep (cognate- dormant)
empezar (ie)- to start, to begin*
encender (ie)- to turn on
encontrar (ue)- to encounter, to find
entender (ie)- to understand
jugar (ue)- to play (a sport, a game)
llover (ue)- to rain
mostrar (ue)- to show
nevar (ie)- to snow
pedir (i)- to request, to ask for
pensar (ie)- to think
pensar + inf.- to intend (to do something)**
pensar + en- to think about someone or something, to reflect on someone or something***
pensar + de- to think (in the sense of having an opinion about something), often used in a question****
perder (ie)- to lose
poder (ue)- to be able to, can
preferir (ie)- to prefer
querer (ie)- to want, to love
recordar (ue)- to remember, to remind
servir (i)- to serve, to be useful
soler (ue) (+inf.)- to be accustomed/ used (to doing something)
volar (ue)- to fly
volver (ue)- to return (to a place)
la hora- hour, time (of day)
*These two verbs are generally used synonymously, with equal frequency.
**This frequent expression is easy to mistranslate as, for example, “I am thinking about …ing.” Be sure to translate it as “I intend to….”
***Pienso mucho en mi abuelo. I think about my grandfather a lot.
****¿Qué piensan Uds. de la nueva ley? What do you think of the new law?
¡Ojo! There are five verbs, four of which appear above, that because of their similarity may cause confusion in reading. These verbs have cognates in English, which may serve as a mnemonic device to help avoid confusion.
|pensar (to think)||is “pensive”|
|perder (to lose)||is “perdition”|
|pedir (to request/ask for)||is “to petition” (Remember that t and d are phonetically related consonants.)|
|poder (to be able to/can)||is “potent”|
|poner (to put)||is “to position” (or “to posit”)|
The relationship between poner and “to position” will be seen in the preterite tense (section 8.2.), which in the first person singular is puse.