Three groups of perfectly regular -ar verbs play a small spelling trick in the preterite yo form: -car verbs swap the c for qu, -gar verbs swap the g for gu, and -zar verbs swap the z for c. The rest of the preterite — tú, él, nosotros, vosotros, ellos — is completely regular. These are not stem changes or irregularities of meaning; they are surface spelling adjustments demanded by Spanish orthographic rules. Once you understand the rules, you can predict every member of all three groups without memorization.
Why the change happens
Spanish spells the same consonant sound with different letters depending on what vowel follows. To keep pronunciation stable, the spelling has to flex. Three pairs are relevant:
- /k/ is written c before a, o, u (casa, comer, cubo) and qu before e, i (queso, quince).
- /g/ is written g before a, o, u (gato, gota, gusto) and gu before e, i (guerra, guitarra).
- /θ/ in peninsular Spanish (and /s/ in seseo dialects) is written z before a, o, u (zapato, zorro, zumo) and c before e, i (cero, cinco).
Now look at what happens in the preterite yo ending, which is -é for all -ar verbs. The vowel that follows the stem consonant changes from a (in the infinitive) to é (in the yo form). The consonant sound must stay the same, so the spelling adapts.
-car verbs: c → qu
Verbs ending in -car change c to qu before -é to preserve the /k/ sound. Without the change, buscé would be pronounced /bus.θe/ in Spain (or /bus.se/ elsewhere) — a completely different word.
| Person | buscar | sacar | tocar |
|---|---|---|---|
| yo | busqué | saqué | toqué |
| tú | buscaste | sacaste | tocaste |
| él/ella | buscó | sacó | tocó |
| nosotros | buscamos | sacamos | tocamos |
| vosotros | buscasteis | sacasteis | tocasteis |
| ellos/ellas | buscaron | sacaron | tocaron |
Other common -car verbs that follow this pattern: explicar (expliqué), practicar (practiqué), aparcar (aparqué), pescar (pesqué), atacar (ataqué), marcar (marqué), comunicar (comuniqué), arrancar (arranqué), publicar (publiqué).
Busqué las llaves por toda la casa y al final estaban en mi bolsillo.
I looked for the keys all over the house and in the end they were in my pocket.
Toqué la guitarra en el concierto del cole y se me cayó la púa al suelo.
I played guitar at the school concert and my pick dropped on the floor.
Aparqué fatal y me llevaron el coche con la grúa.
I parked terribly and they towed my car away.
-gar verbs: g → gu
Verbs ending in -gar insert a silent u between the g and the -é to preserve the hard /g/ sound. Without the u, llegé would be read /ʝe.xe/ (with the /x/ sound of jamón), which would mean nothing.
| Person | llegar | pagar | jugar |
|---|---|---|---|
| yo | llegué | pagué | jugué |
| tú | llegaste | pagaste | jugaste |
| él/ella | llegó | pagó | jugó |
| nosotros | llegamos | pagamos | jugamos |
| vosotros | llegasteis | pagasteis | jugasteis |
| ellos/ellas | llegaron | pagaron | jugaron |
Other common -gar verbs: entregar (entregué), apagar (apagué), colgar (colgué), rogar (rogué), pegar (pegué), regar (regué), tragar (tragué), navegar (navegué), investigar (investigué), madrugar (madrugué).
Llegué tarde a la reunión porque el metro estaba cortado.
I arrived late to the meeting because the metro line was shut down.
Pagué la cena yo, pero la próxima la pagas tú.
I paid for dinner, but next time you're paying.
Anoche jugué al pádel con unos amigos y acabamos cenando juntos.
Last night I played padel with some friends and we ended up having dinner together.
-zar verbs: z → c
Verbs ending in -zar swap z for c before -é. In Spain, both letters represent the same /θ/ sound in this position, so the spelling change is purely orthographic — it does not affect pronunciation. Spanish spelling rules simply forbid the sequence ze in inherited vocabulary, so the c steps in.
| Person | empezar | almorzar | cruzar |
|---|---|---|---|
| yo | empecé | almorcé | crucé |
| tú | empezaste | almorzaste | cruzaste |
| él/ella | empezó | almorzó | cruzó |
| nosotros | empezamos | almorzamos | cruzamos |
| vosotros | empezasteis | almorzasteis | cruzasteis |
| ellos/ellas | empezaron | almorzaron | cruzaron |
Other common -zar verbs: comenzar (comencé), alcanzar (alcancé), abrazar (abracé), rezar (recé), gozar (gocé), tropezar (tropecé), organizar (organicé), realizar (realicé), forzar (forcé), avergonzar (avergoncé).
Empecé a estudiar español en 2019 y todavía me cuesta el subjuntivo.
I started studying Spanish in 2019 and the subjunctive still gives me trouble.
Crucé la calle sin mirar y casi me atropella una bici.
I crossed the street without looking and a bike nearly hit me.
Almorcé en un sitio carísimo del centro — no vuelvo.
I had lunch at a really expensive place downtown — I'm not going back.
What about the -zé pronunciation in Spain?
This deserves a careful note. In peninsular Spanish (distinción), the c before e and the z before a both represent /θ/. So empezar (em-pe-/θ/-ar) and empecé (em-pe-/θ/-é) are pronounced with the same interdental sound. The spelling change does NOT change how it sounds — it just complies with Spanish spelling rules.
In Latin American Spanish (seseo), both c before e and z before a represent /s/. The same spelling rule applies, but the sound is /s/ throughout: empecé is em-pe-/s/-é.
The yo only — nothing else changes
This is the most important point of the whole page. The spelling change affects only the yo form of the preterite. Every other person uses the regular ending without any spelling change, because the endings -aste, -ó, -amos, -asteis, -aron all start with a, o — vowels that don't trigger the change.
Yo empecé el curso en septiembre, pero tú empezaste en octubre.
I started the course in September, but you started in October.
Yo llegué a las ocho y vosotros llegasteis media hora después.
I arrived at eight and you (all) arrived half an hour later.
Yo busqué el archivo, mi compañero lo buscó también, pero al final lo buscaron todos juntos.
I looked for the file, my colleague looked for it too, but in the end everyone looked together.
Note the vosotros forms — buscasteis, llegasteis, empezasteis — are completely regular. This is one of the rare cases where vosotros is the easy form because it sidesteps the spelling issue entirely.
Where else this change appears
The same spelling rule kicks in across the conjugation whenever the next vowel is e or i. You will see it again in:
- The present subjunctive of these verbs (busque, llegue, empiece — all six persons), because the subjunctive endings of -ar verbs all start with -e.
- The affirmative tú imperative stays regular (busca, llega, empieza), but the negative tú imperative uses the subjunctive form (no busques, no llegues, no empieces).
- Formal commands and the usted form (busque usted, llegue usted, empiece usted).
This is the rule, not a list of exceptions: if a back vowel (a/o) is replaced by a front vowel (e/i) in the ending, the spelling of c, g, z must adjust to preserve the consonant sound.
Te pedí que llegaras a tiempo, pero llegaste tarde y empecé sin ti.
I asked you to arrive on time, but you arrived late and I started without you.
Common Mistakes
❌ Yo empezé a trabajar en una panadería.
Incorrect — *empezé* breaks Spanish spelling rules (z + e is not allowed in inherited words). Must be empecé.
✅ Yo empecé a trabajar en una panadería.
I started working at a bakery.
❌ Llegé a casa muerto de hambre.
Incorrect — without the silent u, *llegé* would be pronounced with /x/ (like jefe). Must be llegué.
✅ Llegué a casa muerto de hambre.
I arrived home starving.
❌ Yo buscé un piso barato durante meses.
Incorrect — *buscé* would be pronounced /bus.θe/. Must be busqué to preserve /k/.
✅ Yo busqué un piso barato durante meses.
I searched for a cheap flat for months.
❌ Mis hermanos busquearon el regalo por todas partes.
Incorrect — the spelling change is ONLY in the yo form. Third person plural is buscaron, fully regular.
✅ Mis hermanos buscaron el regalo por todas partes.
My brothers searched for the gift everywhere.
❌ Vosotros empezasteis y yo empezé después.
Incorrect — *empezé* in yo. Vosotros is correct (empezasteis, regular), but yo must be empecé.
✅ Vosotros empezasteis y yo empecé después.
You (all) started and I started afterwards.
Key Takeaways
- The change is spelling-only and happens only in the yo form of the preterite.
- -car → -qué (busqué, saqué, toqué) to preserve /k/.
- -gar → -gué (llegué, pagué, jugué) to preserve /g/; the u is silent.
- -zar → -cé (empecé, crucé, almorcé) because Spanish spelling forbids ze.
- Every other person — tú, él, nosotros, vosotros, ellos — is fully regular.
- The same rule reappears in the present subjunctive (busque, llegue, empiece), where it spreads across all six persons.
Now practice Spanish
Reading grammar gets you part of the way. The exercises are where it sticks — free, no signup needed.
Start learning Spanish→Related Topics
- Cambios ortográficos: -car, -gar, -zarA2 — Why -car, -gar, and -zar verbs look completely regular in the present indicative — and why they suddenly need a c→qu, g→gu, or z→c spelling change as soon as you cross into the preterite or the subjunctive.
- C vs S vs Z: la distinción peninsularA2 — How peninsular Spanish keeps c (before e/i) and z distinct from s in sound, making the spelling system phonetically transparent.
- B vs V: cómo escogerA2 — When to write b and when to write v in Spanish, with the few real rules and the high-frequency words you simply have to memorise.