Yo Irregular verbs are exactly what they sound like: a group of verbs which follow the normal conjugation patterns in all cases except the "Yo" form.
Remember that all regular present tense -Ar, -Er and -Ir verbs are conjugated by removing the -ar, -er,or -ir infinitive endings and adding the correct endings for each conjugation:
|4. +one of the endings: o, as, a, amos, an|
|we end up with conjugated verbs|
|Hablo, Hablas, Habla, Hablamos, Hablan.|
But some verbs conjugate differently in the Yo form. They don't simply add "o".
Dar and Ver are among the irregular Yo form verbs. Because they are three letters long, we have to add a bit more back to the Yo form:
|4. + one of the endings: o, es, e, emos, en|
|5. we end up with: *Vo, ves, ve, vemos, ven|
|6. We can't have *Vo, (Ir already has "VOy") so we have to add the "e" back in for "yo" : V + eo ---->|
Dar adds the "oy" as do Ser, Ir and Estar.
Some irregular "Yo" verbs like Poner, Salir, Oír and Hacer have a "-go" ending for the "yo" form. They are often called "-Go verbs".
Others like Conocer, Traducir and Conducir have a "-zco" ending for the "yo" form and are called "Z verbs" or "-Zco verbs".
|Él, ella, Usted||Pone||Sale||Conoce|
|Ellos, ellas, Ustedes||Ponen||Salen||Conocen|
Saber (to know) has a unique irregular "yo" form, sé , but is regular in all the other forms of conjugation:
Some verbs like Oír not only have an irregular Yo form but also have additional changes.
The yo form is irregular, but so are the other forms. Notice the Nosotros form stays true to the infinitive form, carrying an accented "í".
|yo||tú||Él, ella, Usted||Nosotros||Ellos, ellas, Uds.|