The simple past (pretérito indefinido): Irregular verbs

Irregular preterite: what is really irregular?

• In the preterite (pretérito indefinido) many verbs change their stem, but their endings are almost the same.
• To conjugate them, you usually do two things:
  1. Change to the special stem.
  2. Add the irregular preterite endings.
• If you see two consonants together in the middle (pud-, tuv-, hic- …), that is a good sign you are in the preterite.

Tip: learn these stems as small “blocks” (pud-, pus-, tuv-, hic-) and you will recognise them quickly in texts.

The endings: one set for many irregular verbs

Most irregular stems use the same endings:

• -e, -iste, -o, -imos, -isteis, -ieron
• No accents on any form.

Self‑check: can you say aloud: pude, pudiste, pudo…? If yes, you already control the pattern.

Spelling changes: where and why?

Some changes are only to keep the pronunciation. The meaning does not change.

• -car → -qué in yo
  • buscar → busqué (not buscé)
• -gar → -gué in yo
  • pagar → pagué (not pagé)
• -zar → -cé in yo
  • empezar → empecé (not empezé)

These verbs are otherwise regular in the preterite. Only yo changes.

Vowel changes in -ir verbs (3rd person only)

Some -ir verbs change their vowel only in the 3rd person forms:

• e → i: pedir → pidió, pidieron
• o → u: dormir → durmió, durmieron

Focus: only él / ella / usted and ellos / ellas / ustedes change the vowel.

Consonant changes in 3rd person: -y- verbs

With some verbs like leer, oír, there is a y in 3rd person to avoid three vowels together.

• leer → leyó, leyeron (not leió, leieron)
• oír → oyó, oyeron

All other persons are regular: leí, leíste, leímos, leísteis.

Ser and ir: same forms, different meaning

ser and ir share the same preterite forms:

• Context tells you if it means “was” or “went”.
• Remember: these forms also have no accents.

Accents: when you expect one, but there is none

• All these irregular stems (pud-, tuv-, hic-, etc.), plus ser, ir, dar, ver, have no written accent in the preterite.
• Compare:
  • Regular: preguntó (he asked) → accent on ó.
  • Irregular: pudo (he could) → no accent.

Quick check in your head: if you see an irregular stem, do not add an accent.

Meaning in real life: finished, concrete past actions

You use these forms for completed actions in the past, often with a clear time expression:

• ayer (yesterday)
• anoche (last night)
• el lunes pasado (last Monday)
• el año pasado (last year)

Examples in a professional context:

• Ayer tuve una reunión importante con mi jefe.
• La semana pasada hicimos una presentación para el cliente.
• El año pasado supimos que la empresa cambiaba de sede.

Typical mistakes to avoid

• Adding accents where they do not exist
  • ví → vi
  • estuvó → estuvo
• Using present instead of preterite
  • ayer tengo una reunión → ayer tuve una reunión
• Forgetting spelling changes in yo
  • pagé → pagué
  • empezé → empecé

Step-by-step: how to build the form

1. Identify the infinitive (e.g. poder).
2. Check if it is irregular in the preterite.
   • If yes, find the irregular stem (pud-).
   • If not, use the regular endings for -ar / -er / -ir.
3. Choose the subject (yo, tú, él…).
4. Add the ending for irregular stems:
   • yo → -e, tú → -iste, él → -o, etc.
5. Check accents:
   • Irregular stems, ser, ir, dar, ver → no accent.
   • Regular preterite → accent on yo and él/ella/usted.

Example: “Yesterday I could not join the meeting.”

• Infinitive: poder.
• Irregular stem: pud-.
• Subject: yo.
• Form: no pude.

Mini self‑test: can you do these in your head?

Without looking at the tables, try to say the missing form. Then check.

1. “Last night we were at the office until 10.” → Anoche __________ en la oficina hasta las diez.
   • Answer: estuvimos
2. “Yesterday I put the documents on your desk.” → Ayer __________ los documentos en tu mesa.
   • Answer: puse
3. “They found out the news in the meeting.” → Ellos __________ la noticia en la reunión.
   • Answer: supieron
4. “On Friday he wanted to talk to the director.” → El viernes él __________ hablar con el director.
   • Answer: quiso

If you can solve most of these without checking, you are ready to focus on speaking practice with these forms.