Stem-Changing Verbs: The (o → ue) Pattern
In Spanish, a very common group of verbs undergoes a stem change in the present tense. For these verbs, the vowel o in the stem changes to ue. This occurs in all forms except for nosotros (we) and vosotros (you all). This visual pattern is often called a "boot verb" because the forms that change make the shape of a boot inside a conjugation chart.
This rule applies to many verbs ending in -ar and -er.
1. Model Conjugations
Contar (to count / to tell)
- Yo cuento (I count)
- Tú cuentas (You count)
- Él/Ella/Usted cuenta (He/She counts)
- Nosotros contamos (We count) — No change
- Vosotros contáis (You all count) — No change
- Ellos/Ellas/Ustedes cuentan (They count)
Volver (to return / to come back)
- Yo vuelvo (I return)
- Tú vuelves (You return)
- Él/Ella/Usted vuelve (He/She returns)
- Nosotros volvemos (We return) — No change
- Vosotros volvéis (You all return) — No change
- Ellos/Ellas/Ustedes vuelven (They return)
2. Common Verbs with this Change
Here are frequent verbs that follow this exact pattern:
-AR Verbs:
- Acordarse: to remember (Me acuerdo de ti - I remember you)
- Acostarse: to go to bed
- Almorzar: to have lunch
- Costar: to cost (Cuesta mucho - It costs a lot)
- Encontrar: to find
- Mostrar: to show
- Recordar: to remember / to remind
- Soñar: to dream
- Volar: to fly
-ER Verbs:
- Doler: to hurt (Me duele la cabeza - My head hurts)
- Llover: to rain
- Morder: to bite
- Mover: to move
- Poder: to be able to / can (Yo puedo hacerlo - I can do it)
- Resolver: to solve / to resolve
- Soler: to tend to / to usually do (Suelo leer por la noche - I usually read at night)
3. Special Rules and Irregularities
While the pattern is consistent, a few verbs have unique characteristics:
- Jugar (to play): This is the only verb in Spanish where a u changes to ue.
Example: Yo juego (I play).
- Oler (to smell): In Spanish, words generally cannot begin with the diphthong "ue". Therefore, we add an initial h to the stem-changed forms.
Conjugation: Yo huelo, tú hueles, él huele... but nosotros olemos.
- Weather Verbs: Verbs like llover (to rain) and tronar (to thunder) are rarely used with people. They appear almost exclusively in the third-person singular.
Example: Llueve (It rains / It is raining).
- Spelling Changes (Yo form): Some verbs combine the stem change with a spelling change in the "Yo" form to preserve pronunciation.
- Torcer (to twist): Combines o → ue with a c → z change.
Example: Yo me tuerzo (I twist).
- Cocer (to cook/boil): Combines o → ue with a c → z change.
Example: Yo cuezo (I cook).