Stem Changing Verbs

As one might expect, a Stem Changing verb is a verb where in addition to conjugating (changing the ending) you must also change the stem (the part before the -ar, -er, -ir).  These verbs are also known as "Boot" Verbs.

There are 3 types of Stem Changers:

  1. E-IE
  2. E-I
  3. O-UE (and U-UE)

Here's how they work for an E-IE:

The verb is EMPEZAR.  It is an -ar verb.  So let's take off the ending for a moment and look just at the "stem." 

  1. EMPEZAR
  2. EMPEZ

At this point you see that there are two E's in the stem.  We are only concerned with the one closest to the end (the Red one).  Now we just change the E to IE.

  1. EMPIEZ

Now we are ready to conjugate it:

Empiezo Empezamos
Empiezas Empezáis
Empieza Empiezan

Instantly, you notice that for Nosotros and Vosotros there was no Stem Change.  They do NOT change.  Look at the pattern left when you highlight the stem changers and not nosotros and vosotros.  It looks vaguely like a boot (about as much as Italy does), hence the common name of Boot verb for Stem changing verb.  All stem changing verbs follow this rule of the "Boot."  Never stem change nosotros or vosotros. 

 

Here's how they work for an E-I:

The verb is PEDIR.  It is an -ir verb.  So let's take off the ending for a moment and look just at the "stem." 

  1. PEDIR
  2. PED

At this point you see which E to change in the stem.  We are only concerned with the E closest to the end (the Red one).  If there had been two E's or more, we would still only be concerned with the one closest to the end.  Now we just change the E to I.

  1. PID

Now we are ready to conjugate it:

Pido Pedimos
Pides Pedís
Pide Piden

Instantly, you notice that for Nosotros and Vosotros there was no Stem Change.  They do NOT change.  Look at the pattern left when you highlight the stem changers and not nosotros and vosotros.  It looks vaguely like a boot (about as much as Italy does), hence the common name of Boot verb for Stem changing verb.  All stem changing verbs follow this rule of the "Boot."  Never stem change nosotros or vosotros. 

 

Here's how they work for an O-UE

The verb is Poder.  It is an -er verb.  So let's take off the ending for a moment and look just at the "stem." 

  1. PODER
  2. POD

At this point you see which O to change in the stem.  We are only concerned with the O closest to the end (the Red one).  If there had been two O's or more, we would still only be concerned with the one closest to the end.  Now we just change the O to UE.

  1. PUED

Now we are ready to conjugate it:

Puedo Podemos
Puedes Podéis
Puede Pueden

Instantly, you notice that for Nosotros and Vosotros there was no Stem Change.  They do NOT change.  Look at the pattern left when you highlight the stem changers and not nosotros and vosotros.  It looks vaguely like a boot (about as much as Italy does), hence the common name of Boot verb for Stem changing verb.  All stem changing verbs follow this rule of the "Boot."  Never stem change nosotros or vosotros. 

 

Here is a list (not all inclusive) of Stem Changing verbs by type:

  1. E-IE
empezar to start/begin (like impetus)
comenzar to start/begin (like commence)
preferir to prefer
tener* to have
venir* to come
   
  1. E-I
pedir to ask for
servir to serve
freir to fry
   
  1. O-UE
poder to be able to (to "can")
dormir to sleep
volver to return (people)
devolver to return (items)
   

*U-UE

Jugar is the only verb that changes U to UE and is frequently linked with the O-UE stem changers because of the end result.