Stem-Changing Verbs: 'e' to 'ie'

Verbs Irregular in Irregular Way

Piensa por ti mism@ que no te manipulen.
Sign at a demonstration in Seville, Spain: "Piensa por ti mism@ que no te manipilen." (Think for yourself so they don't manipulate you."). Ana Rey/Creative Commons.

Spanish has dozens of verbs that might be called "regular irregular" verbs — verbs that are irregularly conjugated but are irregular in a consistent way.

These verbs are known as stem-changing or radical-changing verbs, because what makes them irregular is that only the stem (the part of the verb that comes before -ar, -er or -ir) changes from the regular pattern.

For example, any conjugation of the regular verb hablar, whatever the tense or mood, starts with habl-. But the verb pensar, which usually means "to think," can have its stem change. Fortunately, the stem changes in a predictable way: The e changes to ie whenever it is stressed. When the stem isn't stressed, the e remains unchanged.

This summary shows the irregular forms in boldface. All conjugated forms not shown are regular:

  • Present indicative: yo pienso (I think), piensas (you think), usted/él/ella piensa (you think, he/she thinks), nosotros/as pensamos (we think), vosotros/as pensáis (you think), ustedes/ellos/ellas piensan (you/they think).
  • Present subjunctive: que yo piense (that I think), pienses (that you think), usted/él/ella piense (that you think, he/she thinks), nosotros/as pensamos (we think), vosotros/as pensáis (that you think), ustedes/ellos/ellas piensan (that you/they think).
  • Imperative: piensa (think), no pienses (don't think), piense usted (think), pensemos nosotros/as (let's think), pensad vosotros/as (think), no penséis vosotros/as (don't think), piensen ustedes (think).

Other verbs that are conjugated in exactly this pattern include acertar, alentar, apretar, arrendar, atravesar, calentar, cerrar, confesar, encerrar, enterrar, gobernar, helar, manifestar, merendar, recomendar, reventar and sembrar.

A similar pattern can be seen with verbs such as entender, which usually means "to understand." The stem of entender changes in the same way as does the stem of pensar, but the verb has some differences in conjugation because it is an -er verb rather than an -ar verb. Verbs that are conjugated in the same way as entender include ascender, atender, cerner, cotender, defender, descender, distender, heder, perder, trascender and verter.

  • Present indicative: yo entiendo (I understand), entiendes (you understand), usted/él/ella entiende (you understand, he/she understands), nosotros/as entendemos (we understand), vosotros/as entendéis (you understand), ustedes/ellos/ellas entienden (you/they understand).
  • Present subjunctive: que yo entienda (that I understand), entiendas (that you understand), usted/él/ella entienda (that you understand, he/she understands), nosotros/as entendamos (we understand), vosotros/as entendáis (that you understand), ustedes/ellos/ellas entiendan (that you/they understand).
  • Imperative: entiende (understand), no entiendas (don't understand), entienda usted (understand), entendamos nosotros/as (let's understand), entendad vosotros/as (understand), no entendáis vosotros/as (don't understand), entiendan ustedes (understand).

Related Conjugation Patterns

There are a few verbs that have the e-to-ie stem change but are also irregular in other ways. For example, querer has the stem change, and additionally the r of its stem sometime changes to rr. The verb despertar (to get up) followed the e-to-ie pattern but also has an irregular past participle, despierto.

Also, many of the -ir verbs that are irregular, such as sentir and mentir, sometimes follow the pattern of this lesson but can have the e of the stem change to i.

Sample Sentences Showing the Stem Change

Stem-changing verbs are shown in boldface:

  • Si ninguno confiesa, ambos estarán en prisión sólo un mes. (If no one confesses, both will be in prison for just a month.)
  • ¿Cuándo se cierran las escuelas debido al mal tiempo? (When do they shut the schools because of bad weather?)
  • Te recomiendo que te despiertes temprano y te divierte andando a la playa. (I recommend you get up early and enjoy yourself walking to the beach.)
  • ¡Defiende tu castillo! Defend your castle!
  • Entiendo que la enfermera atiende a una persona en esta situación. (I understand that the nurse attends to a person in this situation.)
  • El huésped y el pez, a los tres días hieden. At three days the guest and the fish stink.