PRESENT PERFECT - Regular past participles 1

Regular past participles — two patterns — -ar verbs: drop -ar, add -ado: hablar → hablado, caminar → caminado, trabajar → trabajado. -er/-ir verbs: drop ending, add -ido: comer → comido, vender → vendido, vivir → vivido. These patterns cover the vast majority of Spanish verbs.

Accented -ído for certain -er/-ir verbs — When the verb stem ends in a vowel, the -ido ending takes a written accent (-ído) to prevent the vowels merging into a diphthong: caer → caído, leer → leído, traer → traído, oír → oído. The accent preserves the two-syllable pronunciation: ca-í-do, not cai-do.

Two uses of past participles — Regular past participles are used in two main ways: (1) as part of a compound tense after haber (invariable): He hablado, han comido. (2) as an adjective after estar (agrees in gender and number): Estoy cansado/a. Las puertas están cerradas. The context tells you which function applies.