Stem-changing verbs in the Spanish present tense

What is a stem change?

The stem is the infinitiveinfinitiveThe basic form of a verb, e.g. hablar, comer or vivir. without -ar, -er or -ir: quer- in querer🔊, pod- in poder🔊. With a stem change, the vowelvowelA sound like a, e, i, o, or u, and the letter used to write it. in this stem changes: quiero🔊, puedo🔊. The endings stay completely normal, just as you know them from regular verbs.

The change only happens when the stress falls on the stem, i.e. with yo🔊, tú🔊, él🔊/ella🔊 and ellos🔊/ellas🔊. With nosotros🔊 and vosotros🔊 the stress falls on the ending, so the stem stays as in the infinitiveinfinitiveThe basic form of a verb, e.g. hablar, comer or vivir.: queremos🔊, podemos🔊.

e → ie

-e- in the stem becomes -ie-. This is how querer🔊 (to want), pensar🔊 (to think), empezar🔊 (to start), entender🔊 (to understand) and preferir🔊 (to prefer) work.

Quiero aprender español.🔊 (I want to learn Spanish.) ¿A qué hora empieza la clase?🔊 (What time does the class start?) Prefiero el té.🔊 (I prefer tea.)

o → ue

-o- in the stem becomes -ue-. This is how poder🔊 (can, to be able to), dormir🔊 (to sleep), encontrar🔊 (to find) and volver🔊 (to come back) work. You already know ¿Cuánto cuesta?🔊 (How much does it cost?): cuesta🔊 comes from costar🔊.

¿Puedes ayudarme?🔊 (Can you help me?) Ella vuelve a casa.🔊 (She comes back home.) Mi hermano duerme mucho.🔊 (My brother sleeps a lot.)

e → i

-e- in the stem becomes -i-. This pattern only exists in verbs ending in -ir, for example pedir🔊 (to order, to ask for) and repetir🔊 (to repeat).

Siempre pido un café.🔊 (I always order a coffee.) Pedimos la cuenta.🔊 (We ask for the bill.) – no change here with nosotros🔊.

A special case: jugar

jugar🔊 (to play) is the only common verb in which -u- becomes -ue-: juego🔊, juegas🔊, juega🔊, jugamos🔊, jugáis🔊, juegan🔊. Los niños juegan al fútbol.🔊 (The children play football.) In parts of Latin America people also say jugar fútbol🔊, without al🔊.

vosotros or ustedes?

vosotros🔊 (you, pluralpluralThe grammatical form used for more than one person or thing.) is only used in Spain. In Latin America people always say ustedes🔊 to several people, with the same form as ellos🔊: ¿Ustedes quieren un café?🔊 (Do you want a coffee?) That is why the exercises mainly use yo🔊, tú🔊, él🔊/ella🔊, nosotros🔊 and ellos🔊/ustedes🔊.