A1
Stem-changing verbs
How Spanish stem-changing verbs work, the three patterns, and why the nosotros form is always regular.
A large group of Spanish verbs change their stem vowel in the present — but only in the four forms where the stress lands on that vowel.
e → ie
| quiero | |
| quieres | |
| quiere | |
| queremos | unchanged |
| queréis | unchanged |
| quieren |
Quiero un café.
I-want a coffee
I’d like a coffee.
Others: pensar → pienso, empezar → empiezo, entender → entiendo, preferir → prefiero.
o → ue
Poder → puedo, dormir → duermo, volver → vuelvo, encontrar → encuentro, costar → cuesta.
¿Cuánto cuesta?
how-much costs
How much is it?
e → i
Only -ir verbs: pedir → pido, servir → sirvo, repetir → repito.
Pido la cuenta.
I-ask-for the bill
I’ll ask for the bill.
nosotros is never affected
The stress moves onto the ending in queremos and podemos, so the stem vowel is unstressed and stays as it is. This is the whole logic of the pattern, and knowing it means never having to memorise which form is the exception.
Nosotros puedemos ir.
Nosotros podemos ir.
The change happens only under stress. Podemos stresses -de-, so the o stays. The same goes for queremos, dormimos and entendemos.
The dictionary will not tell you
Nothing in poder or contar marks them out. Stem-changing verbs are learnt one at a time, usually written poder (ue) in a wordlist.