1. The Present Tense of Stem-Changing Verbs: e  ie, e  i, o  ue, u ue
(El tiempo presente de los verbos de cambio radical)

2. Stem changing infinitives are named for what they do– change in the stem.
There are some mixed verbs : “Go” verbs and “stem changing” in the same time
We always change the vowel that is the closest to the ending
The ending terminations depend on the ending or each verb : AR, ER or IR terminations

3. There are four types or classes of “boot” verbs.
There is a fairly large group of verbs in Spanish that undergo changes in their stem when conjugated in the present tense. These changes occur only in the first and second persons singular and third persons singular and plural.
When a line is drawn around the forms that change, the resulting shape vaguely resembles a boot or high-top shoe; thus, these verbs are sometimes informally called “boot” or “shoe” verbs.
There are four types or classes of “boot” verbs.

4. Type 1: e  ie entender entiendo entiendes entiende entendemos
We’ll use entender, to understand, as an example of this type.
entender
entiendo
entiendes
entiende
entendemos
entendéis
entienden
The stem undergoes the change only when stressed.

5. Here are some other common e  ie verbs:
empezar, comenzar
to begin
pensar
to think
perder
to lose
preferir
to prefer
querer
to want, to love
entender
to understand

6. Tener (to have), venir (to come)
The verbs tener and venir are what might be called partial stem-changing verbs; the yo forms do not have the stem change, but they do have an irregularity.
tengo
tienes
tiene
tenemos
tenéis
tienen
Tengo exámenes mañana.
I have exams tomorrow.
vengo
vienes
viene
venimos
venís
vienen
Vengo de la biblioteca.
I’m coming from the library.

7. Type 2: e  i servir sirvo sirves sirve servimos servís sirven
We’ll use servir, to serve, as an example of this type.
servir
sirvo
sirves
sirve
servimos
servís
sirven
Note: All e  i verbs are -ir verbs.

8. Here are some other common e  i verbs:
repetir
To repeat
pedir
To ask for, to order
reir
To laugh
sonreir
To smile
seguir
To follow
decir
To say, to tell

9. We’ll use almorzar, to have lunch, as an example of this type.
Type 3: o  ue
We’ll use almorzar, to have lunch, as an example of this type.
almorzar
almuerzo
almuerzas
almuerza
almorzamos
almorzáis
almuerzan

10. Here are some other common o  ue verbs:
almorzar
To have lunch
dormir
to sleep
encontrar
to find
poder
to be able; can
recordar
to remember
soñar (con)
to dream (about)
volver
to return (to a place)
devolver
To return (something)

11. Type 4: u  ue jugar jugamos juego jugáis juegas juegan juega
The verb jugar, to play (games or sports), follows the same pattern as o  ue verbs, but the change is u  ue.
jugar
juego
juegas
juega
jugamos
jugáis
juegan

12. FIN