Spanish preterite irregular notes

-car

-car → -qué (only affects yo form)

-gar

-gar → -gué (only affects yo form)

-zar

-zar → -cé (only affects yo form)

uv in the stem irregular

estar → estuv-, andar (to walk) →anduv-, tener → tenuv-

j in the stem irregular

Traer (to bring)→ Traj-, Traducir (to translate) → Traduj-, Producir (to produce) → Produj-

Note that the i part in ieron (ustedes) is removed (eg. Trajeron, Tradujeron, Produjeron)

u in the stem irregular

Saber (to know) → sup-, Poder → pud-, Poner (to put) → pus-, Caber (to fit) → Cup-, Haber (to have) → hub-

i in the stem irregular

Hacer → Hic-, Venir (to come) → Vin-, Querer → Quis-, Decir → Dij-

y stem chaning irregular

Only applies for third person (El, Ella, ellos, ellas). In those verbs, a y is added after the stem. Examples of verbs that adapt this are: Leer, creer, caer, oir, construir, etc.

Irregular endings (excluding -car, -gar, -zar, ir, ser, dar, ver)

-e, -iste, -o, -imos, -ieron