An irregular verb does not follow the conjugation pattern corresponding to its infinitive ending. All the tenses or some of them may be irregular, the root or the endings may follow different patterns. It is not necessary to study all the conjugation of a verb to check: if a verb do not has the irregular present indicative, the preterit or the future, this verb is not irregular.

1 The orthographic changes to keep the sound are not considered irregularities.

See Spelling: general

  • Verbs ending in -car: yo pesqué, tú pescaste, etc.
  • Verbs ending in -cer, -cir: vencer, venzo, etc.
  • Verbs ending in -gar: llegué, llegar, etc.
  • Verbs ending in -ger, -gir: elegir, elijo; coger, cojo, etc.
  • Delinquir: delinco.
  • Verbs ending in -guir: distinguir, distingo; seguir, sigo, etc.
  • Verbs ending in -zar: almorzar, almorcé; alzar, alcé, etc.
  • Verbs ending in -guar: apaciguar, apacigüé, etc.
  • Some verbs ending in -aer, -eer, -oer, -uir, errar and argüir bear y instead of i between vowels or at the beginning of the word: leyó, leer; oír, oyó; huir, huyó; errar, yerro, etc.

2 Irregular verbs

The irregular verbs may have:

  • Changes vowel – diphthong: niego, negar; entiendo, entender, etc.
  • Insertion of a letter: conozca, conocer; nazca, nacer, etc.
  • Changes in the stressed syllable: ríes, reír; ciñes, ceñir, etc.
  • Removal of a sound: gruñir, gruñó, etc.