irregular present (2)

Predictable Irregularities: Verbs ending in -cer and -cir

In Spanish, there is a large family of verbs that follow a very specific and predictable irregular pattern in the Present Indicative tense. This rule applies to verbs where the infinitive ends in a vowel + -cer or a vowel + -cir.

The Rule

For these verbs, you must change the c to zc in the first-person singular (yo) form.

Important: All other forms (tú, él/ella, nosotros, vosotros, ellos/ellas) remain completely regular.

The Model: Conocer (to know)

The most common verb in this group is conocer. Notice how only the "Yo" form changes:

• Yo conozco (I know) — Irregular change c → zc
• Tú conoces (You know)
• Él/Ella/Usted conoce (He/She/You know)
• Nosotros/as conocemos (We know)
• Vosotros/as conocéis (You all know)
• Ellos/Ellas/Ustedes conocen (They/You all know)

Common -ER Verbs in this Group

Many verbs ending in -er follow this exact pattern. Here are the most useful ones with their irregular "Yo" form:

• Agradecer (to thank) → Yo agradezco
• Aparecer (to appear) → Yo aparezco
• Crecer (to grow) → Yo crezco
• Establecer (to establish) → Yo establezco
• Ofrecer (to offer) → Yo ofrezco
• Pertenecer (to belong) → Yo pertenezco
• Reconocer (to recognize) → Yo reconozco

Common -IR Verbs in this Group

Several verbs ending in -ir also follow this rule:

• Conducir (to drive) → Yo conduzco
• Producir (to produce) → Yo produzco
• Traducir (to translate) → Yo traduzco

Exceptions

Note that this rule requires a vowel before the ending. Verbs like hacer (to do/make) or vencer (to defeat) do not follow this pattern because they are not preceded by a vowel in the same way or have their own unique irregularities.

Examples in Context