Spanish Stem-Changing Verbs
Being able to identify verbs in Spanish and how to properly change their stem, will help you greatly in order to improve your communication skills. Since you already know what a verb is, let's talk about the different ways in which the verbs can be conjugated by identifying the stem of the verbs and their endings; also known as stem change.
What is a Stem Change?
Remember the two ways in which the verbs venir "to come" and tener "to have" were irregular? First, their yo form had a g before the o, and second, they had a stem change in the tú, usted, and ustedes forms.
This notion of a stem change will become quite familiar to you over time, as many Spanish verbs are stem changing in every form exept nosotros/as and vosotros/as.
Let’s go back and review what a stem is. The stem of a verb is the part of the verb that is left once you take away the –ar, -er, or –ir ending. In regular verbs, the stem does not change no matter what ending you add on to it..
However, in stem changing verbs, the stem will change in every form but two. There are three common types of stem changing verbs: e to ie, e to i, and o to ue.
Review the following examples:
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e to ie: COMENZAR "to begin"
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e to i: MEDIR "to measure"
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o to ue: DORMIR "to sleep"

A Rare Stem Change: i to ie
The stem change patterns above are the most common, but you will find a few verbs that make a different stem change: from i to ie.
Adquirir "to acquire"
Inquirir "to inquire / to investigate"
Another Rare Stem Change: u to ue
A verb that you will use often in Spanish is jugar "to play." Jugar is a stem-changing verb with a u to ue stem change.

The Last and Strangest Stem Change: o to hue
Last of all, you should note that the verb oler "to smell" is also irregular. You’ll need to memorize this stem change if you want to talk of smelling the roses.
Check out more Spanish Verbs for useful info! Here are some recommended lessons:
- Spanish Verbs - Saber and Conocer
- Spanish Verbs in the Present Tense and Conjugations
- Spanish Verbs Decir & Dar
See you soon! ¡Hasta pronto!
Mauricio Evlampieff: Rocket Spanish