[Present] [Preterit] [Imperfect] [Present Participle] [Past Participle] [Present Subjunctive] [Imperfect Subjunctive] [Future] [Conditional]
Present:
Stem-changing verbs have a change in spelling and pronunication in the stem in all forms except the nosotros and vosotros. The change occurs in the stressed syllable of the conjugated verb which is also the last syllabus of the infinitive. All stem-changing verbs are noted in dictionary listings by indicating the change in parentheses. There are four categories: e -- ie, o -- ue, e -- i, and u -- ue (jugar is only the only verb of such a category)
 
pensar (ie)
volver (ue)
pedir (i)
pienso
pienso
piensa
pensamos
pensáis
piensan
vuelvo
vuelves
vuelve
volvemos
volvéis
vuelven
pido
pides
pide
pedimos
pedís
piden
 
Stem-changing verbs that also have irregular yo form include: decir -- digo, tener -- tengo, venir -- vengo.
Preterit:
Stem-changing verbs ending in -ir only have a stem change in the 3rd person singular and plural.In dictionary listings the second vowel or combination after a verb refers to a change in preterit (also present participle  and present subjunctive).
 
dormir (ue, u)
mentir (ie, i)
vestirse (i, i)
dormí
dormiste
d-u-rmió
dormimos
dormisteis
d-u-rmieron
mentí
mentiste
m-i-ntió
mentimos
mentisteis
m-i-ntieron
me vestí
te vestiste
se v-i-stió
nos vestimos
os vestisteis
se v-i-stieron
Imperfect:
None.
Present Participle:
A. The -ir sten changers have a change in the stem: dormir (ue, u) -- durmiendo, vestir (i, i) -- vistiendo, sentir (ie, i) -- sintiendo.
In dictionary listings the second vowel or combination after a verb refers to a change in present participle (also preterit and present subjunctive).
B. Verbs ending in a vowel + er/ir (except for a silent -u- as in seguir) take a -y- instead of -i- in the ending: leer -- le-y-endo, destruir -- destru-y-endo.
Past Participle:
None.
Present Subjunctive:
 
  • All -ar and -er stem-changing verbs have the same changes as in the present indicative tense.
  • All -ir stem-changing verbs have the same  as in the present indicative tense except for the nosotros and vosotros forms, which require a different stem-change. It is a change which is second in dictionary listings. It also refers to a change in present participle and preterit.
  • Certain verbs are regular but need spelling changes to preserve the pronunciation.

    •  
     
    almorzar
    sentir
    dormir
    pedir
    pagar
    elegir
    sacar
    cazar
    almuerce
    almuerces
    almuerce
    almorcemos
    almorcéis
    almuercen
    sienta
    sientas
    sienta
    sintamos
    sintáis
    sientan
    duerma
    duermas
    duerma
    durmamos
    durmáis
    duerman
    pida
    pidas
    pida
    pidamos
    pidáis
    pidan
    pague
    pagues
    pague
    paguemos
    paguéis
    paguen
    elija
    elijas
    elija
    elijamos
    elijáis
    elijan
    saque
    saques
    saque
    saquemos
    saquéis
    saquen
    cace
    caces
    cace
    cacemos
    cacéis
    cacen
    Imperfect Subjunctive:
    None, since all are based on 3rd person plural of the preterit.
    Future:
    None.
    Conditional:
    None.