Present-Tense O to UE Stem-Changing Verbs
Poder, volver, and dormir follow a shared vowel change that appears in predictable places. Practise the altered stem without losing the regular present endings.
Learning objective
Conjugate frequent O to UE stem-changing verbs in useful present-tense statements and questions.
A verb’s stem is the main part left after removing its infinitive ending. Some frequent present-tense verbs change o to ue inside this stem. Poder, to be able to, gives puedo, puedes, puede, podemos, podéis, and pueden. The normal endings still identify the subject; the internal vowel changes except in the nosotros and vosotros forms.
Volver, to return, and dormir, to sleep, share the placement: vuelvo but volvemos, and duermes but dormimos. This is not an instruction to change every o you see. Comer remains como, and tomar remains tomo, so learn a new verb with a model pair such as puedo–podemos.
Poder commonly introduces another infinitive: Hoy puedo cocinar means I can cook today. English uses can plus a plain verb, while Spanish conjugates poder and leaves the following action in its infinitive form. Avoid conjugating both verbs in this two-verb group: puedo cocinar, not puedo cocino.
A connected evening plan displays the pattern naturally: ¿Puedes volver temprano? No, pero puedo llamar. Después, dormimos en casa de Ana. The first two speakers use changing forms, while the group’s dormimos keeps o. Meaning and participants make the contrast memorable.
Examples
Puedo ayudarte cuando vuelvo del trabajo.
I can help you when I get back from work.
Puedo and vuelvo both change o to ue for yo.
¿Duermes bien cuando viajas?
Do you sleep well when you travel?
Duermes shows the change in an informal singular question.
No podemos salir porque llueve mucho.
We can’t go out because it is raining heavily.
Podemos retains o with nosotros; no appears before the conjugated verb.
Ellas vuelven tarde, pero nosotros volvemos antes.
They return late, but we return earlier.
Vuelven contrasts directly with unchanged volvemos.
Common mistake
- Instead of
- Nosotros puedemos dormir y ella pode volver.
- Try
- Nosotros podemos dormir y ella puede volver.
Podemos is the unchanged nosotros form, while puede is the changed third-person form. Spanish conjugates poder rather than copying English can unchanged across subjects. The following actions dormir and volver correctly remain infinitives.
Practice
Try it yourself
Complete this travel update with poder, volver, and dormir: Yo no ___ salir hoy. Mis amigas ___ mañana. Nosotros ___ aquí esta noche y mañana ___ viajar juntos.