The Past Participle in English and Spanish
In English, the regular past participle form of the verb ends in -ed (talked, walked). We have many irregular forms of the past participle like gone, sung, rang. The new English student must simply memorize these irregular forms.
In Spanish, the regular past participle form of the verb ends in -ado (for -ar verbs) and -ido (for -er and -ir verbs). Spanish drops the -ar, -er, and -ir endings and adds these endings to regular verb stems. (The verb stem is what we get when we drop the endings; hence, the verbv stem for hablar is habl-.) Hablar (to speak) becomes hablado (spoken) -- notice how what is regular in Spanish is sometimes irregular in English, and vice versa.) Beber and vivir (to drink and to live) become bebido and vivido (drank and lived).
As in English, there are a number of irregular Spanish past participle verb forms that also must be learned and memorized. The most common irregular past participles in Spanish are:
Infinitive - Irregular past participle
abrir (to open) - abierto (opened)
caer (to fall) - caido (fallen)
*cubrir (to cover) - cubierto (covered)
decir (to say, to tell) - dicho (said, told)
*descubrir (to discover) - descubierto (discovered)
escribir (to write) - escrito (written)
*hacer (to do, to make) - hecho (done, made
imprimir (to print) - impreso (printed)
morir (to die) - muerto (died)
poner (to put) - puesto (put)
romper (to break) - roto (broken)
ver (to see) - visto (seen)
volver (to return) - vuelto (returned)
*Note: Derivative forms of these verbs have similar irregular past participle. For example deshacer (to undo) becomes deshecho (undone).