Past participles: a special type of verb. Participles in English are verbs such as eaten, washed, written, and the like. In both Spanish and English, past participles are used to accompany all of the perfect tenses. English has four present tenses; Spanish has six. But the perfect tenses will be covered later.
To make an infinitive a past participle, you must first remove the -ar, -er or -ir ending from the verb. Let's take three examples:
hablar →habl-
ser →s-
vivir →viv-
After that, you must add the participle ending to it. For -ar verbs, the ending is -ado. For -er and -ir verbs, it's -ido. So let's conjugate these verbs:
Hablar → hablado
ser → sido
vivir → vivido
There are many irregular past participles, and there's an external link to one of my favorite resources, SpanishDict, where they give a list of irregular past participles.
"But wait!" You might be asking. "Joye, how do we know which person is being referred to if there's only one stem?"
That is a great question! But that will be covered in the next 3 chapters, where we talk about how to conjugate in past, present, and future perfect tense.