Partially irregular verbs change a vowel or a consonant in some forms.

Groups of partially irregular verbs are characterized by:

• exchange o: ue
• exchange o: ue: u
• exchange e: ie
• exchange e: i
• exchange e: ie: i
• exchange c: zc
• exchange u: uy.

These verbs change o to ue in following forms:

• in the 1st, 2nd and 3rd person singular and 3rd person plural of presente and presente de subjuntivo;
• in the 2nd person singular imperativo.

The other forms are regular.

Among others, included here are: acordar, consolar, amoblar, clocar, almorzar, follar, hollar, soltar, sonar, soñar, tonar, doler, volver, torcer, moler, soler, llover.

Forms with the exchange:

presente de indicativo

presente de subjuntivo

imperativo

This group includes only dormir i morir.

These verbs change o to ue in following forms:

• in the 1st, 2nd and 3rd person singular and 3rd person plural of presente and presente de subjuntivo;
• in the 2nd person singular imperativo.

The other forms are regular.

Additionally, they change o into u in:

• 3rd person of singular and plural of pretérito simple (durmió, durmieron);
• 1 i 2 persons plural presente de subjuntivo (durmamos, durmáis);
• in all persons of tenses: pretérito imprefecto de subjuntivo, futuro simple de subjuntivo;
• in gerundio.

These verbs change e to ie in following forms:

• in the 1st, 2nd and 3rd person singular and 3rd person plural of presente and presente de subjuntivo;
• in the 2nd person singular imperativo.

The other forms are regular.

Among others, included here are: acertar, alentar, atravesar, calentar, confesar, comenzar, despertar, empezar, pensar, quebrar, regar, segar, defender, encender, perder, verter, discernir.

Forms with the exchange:

presente de indicativo

presente de subjuntivo

imperativo

These verbs change e to i in following forms:

• in the 1st, 2nd and 3rd person singular and 3rd person plural of presente and presente de subjuntivo;
• in the 2nd person singular imperativo ;
• in the 3rd person of singular and plural of pretérito simple (durmió, durmieron);
• in all simple tenses of subjuntivo;
• in gerundio.

Among others: pedir, elegir, medir, gemir, rendir, vestir.

Conjugation in presente:

These verbs change e to ie in following forms:

• in the 1st, 2nd and 3rd person singular and 3rd person plural of presente and presente de subjuntivo;
• in the 2nd person singular imperativo.

The other forms are regular.

Additionally, they e into i in:

• 3rd person of singular and plural of pretérito simple (sintió, sintieron);
• 1 and 2 person plural of presente de subjuntivo (sintamos, sintáis);
• in all persons of tenses: pretérito imprefecto de subjuntivo, futuro simple de subjuntivo;
• in gerundio.

Among others belong here: sentir, mentir, digerir, advertir.

These verbs change c to zc w formach:

• 1st person of presente de indicativo;
• in all forms of presente de subjuntivo.

Among others: nacer, cocer, parecer, conocer.

These verbs change u to uy in following forms:

• in the 1st, 2nd and 3rd person singular and 3rd person plural of presente and presente de subjuntivo;
• in the 2nd person singular imperativo.

The other forms are regular.

The group includes among others : atribuir, destruir, huir, diluir.

Conjugation in presente: