what is it?
Certain Spanish verbs require a spelling adjustment in the first-person singular (yo) of the preterite. The change is purely orthographic: it exists to keep the final consonant sound of the stem identical to the infinitive. Verbs ending in -car, -gar, and -zar are the three groups affected. All other persons of these verbs are completely regular.
when to use it
Apply the spelling change whenever all three conditions are met:
The verb ends in -car, -gar, or -zar. Examples: buscar, tocar, llegar, pagar, empezar, cruzar.
The tense is the preterite (pretérito indefinido). These changes do not occur in the present or imperfect.
The subject is yo. The change affects only the yo-form. Every other person uses the regular spelling.
The reason: Spanish spelling rules require qu before e to represent the /k/ sound, gu before e to represent the /g/ sound, and c before e to represent the /θ/ (or /s/) sound. Without the adjustment, the pronunciation would shift.
formation
Remove the infinitive ending and apply the adjusted yo-form. All other preterite endings are standard. The table below shows the yo-form alongside the él/ella-form to illustrate that only yo changes.
| infinitive | stem change | yo (preterite) | él/ella (preterite) |
|---|---|---|---|
| buscar | -car → -qué | busqué | buscó |
| tocar | -car → -qué | toqué | tocó |
| llegar | -gar → -gué | llegué | llegó |
| pagar | -gar → -gué | pagué | pagó |
| empezar | -zar → -cé | empecé | empezó |
| cruzar | -zar → -cé | crucé | cruzó |
The full preterite paradigm for llegar shows that only the yo-form is irregular in spelling:
| person | form |
|---|---|
| yo | llegué |
| tú | llegaste |
| él / ella / usted | llegó |
| nosotros | llegamos |
| vosotros | llegasteis |
| ellos / ustedes | llegaron |
examples in context
common pitfalls
Dropping the spelling change entirely. Writing «llegé», «buscé», or «empezé» applies the standard -é ending directly to the infinitive stem. This produces the wrong consonant sound before e. The correct forms are llegué, busqué, and empecé.
Spreading the yo-form spelling to other persons. The yo-form change is exclusive to yo. Writing «busqó» or «empecó» for the él/ella-form is incorrect. Those forms are buscó and empezó — the regular spelling, because the ending -ó does not trigger any adjustment.
Confusing the -zar group. Learners sometimes write «empezé» or «cruzé», treating -zar like a regular verb. Remember that z becomes c before e in Spanish orthography, so the correct yo-forms are empecé and crucé.