Spanish present tense consonant change c > zc in -cer/-cir verbs

Written by qualified Spanish expert Inma Sánchez BA

Last updated: 2022-12-21

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In Spanish, the -c changes to a -zc in El Presente for many verbs that end in -cer/-cir that are preceded by a vowel. This only affects the yo form. Have a look at these two verbs conjugations in El Presente.

Vowel+CER verb	CONOCER (to meet/know)
yo	conozco
tú	conoces
él / ella / usted	conoce
nosotros/nosotras	conocemos
vosotros/vosotras	conocéis
ellos/ellas/ustedes	conocen

Vowel+CIR verb	PRODUCIR (to produce)
yo	produzco
tú	produces
él /ella/usted	produce
nosotros/nosotras	producimos
vosotros/vosotras	producís
ellos/ellas/ustedes	producen

Here are some examples:

Esa fábrica produce mucho plástico.That factory produces a lot of plastic.

¿Vosotros producís aceite de oliva virgen?Do you produce virgin olive oil?

Nosotros no conocemos a mucha gente en este pueblo.We don't know many people in this village.

Ellos no conocen a la novia de Miguel.They don't know Miguel´s girlfriend.

Yo conozco a David Martínez.I know David Martínez.

¿Tú conoces a mi amiga Marta?Do you know my friend Marta?

¿Ustedes no conocen el restaurante El Faro?Don't you know restaurant El Faro?

Note that common verbs hacer (to do/make) and decir (to say) do not have this type of irregularity! They are still irregular though, see Verbos yo-go (presente).

For other verbs within this same irregularity see:

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