Some Brazilian Portuguese verbs swap a letter or two when you conjugate them — ficar becomes fiquei, começar becomes começo — and beginners often panic, thinking these are irregular. They are not. The sound never changes; only the spelling adjusts so that the sound can stay the same. Once you understand the handful of spelling rules behind these swaps, every one of them becomes completely predictable.
Why this happens at all
Brazilian Portuguese spelling has a built-in problem: the letters c and g are pronounced differently depending on the vowel that follows them.
- c is hard /k/ before a, o, u (casa, copo, cubo) but soft /s/ before e, i (cedo, cidade).
- g is hard /g/ before a, o, u (gato, gota, gula) but soft /ʒ/ before e, i (gente, gira).
So when a verb's sound stays constant but the following vowel changes during conjugation, the spelling has to bend to keep the sound intact. That is the entire story. Nothing about the verb's pronunciation is irregular — the spelling is just doing its job.
English speakers actually do something similar without thinking: we write "picnic → picnicked" (adding a k) so the c stays hard. Portuguese just has a fuller system of these guards.
Pattern 1: c → qu before e/i
Verbs ending in -car keep the hard /k/ sound everywhere. But whenever an ending starts with e or i, a plain c would go soft (/s/), so the spelling switches to qu, which is always hard.
Take ficar (to stay, to be located):
| Form | Spelling | Why |
|---|---|---|
| eu fico (present) | fico | c before o = hard /k/, no change needed |
| eu fiquei (preterite) | fiquei | before -ei, c → qu to keep /k/ |
| que eu fique (subjunctive) | fique | before -e, c → qu to keep /k/ |
Other -car verbs that behave identically: brincar (to play), tocar (to touch/play music), buscar (to fetch), explicar (to explain), ficar.
Eu fiquei em casa o fim de semana inteiro.
I stayed home the whole weekend.
Brinquei muito com meus primos quando era criança.
I played a lot with my cousins when I was a kid.
Espero que você fique mais um pouco.
I hope you stay a little longer.
Pattern 2: g → gu before e/i
The exact same logic, one row down the alphabet. Verbs in -gar keep the hard /g/. Before e or i, a plain g would go soft (/ʒ/), so it becomes gu.
Take chegar (to arrive):
| Form | Spelling | Why |
|---|---|---|
| eu chego (present) | chego | g before o = hard /g/ |
| eu cheguei (preterite) | cheguei | before -ei, g → gu to keep /g/ |
| que eu chegue (subjunctive) | chegue | before -e, g → gu to keep /g/ |
Other -gar verbs: pagar (to pay), jogar (to play/throw), chegar, pegar (to grab), entregar (to deliver).
Cheguei atrasado de novo, desculpa.
I arrived late again, sorry.
Já paguei a conta pelo aplicativo.
I already paid the bill through the app.
Tomara que eles cheguem antes da chuva.
Hopefully they'll arrive before the rain.
Pattern 3: c → ç before a/o
Now flip the direction. Verbs in -çar need the soft /s/ sound. A plain c stays soft only before e/i — but before a or o it would go hard (/k/). To keep the /s/, the spelling uses ç (c-cedilha), which is always /s/.
Take começar (to begin):
| Form | Spelling | Why |
|---|---|---|
| eu começo (present) | começo | before o, c → ç to keep /s/ |
| você começa | começa | before a, c → ç to keep /s/ |
| eu comecei (preterite) | comecei | before -ei, plain c is already soft /s/ |
| que nós comecemos | comecemos | before -e, plain c is already soft /s/ |
Notice it's the infinitive's ç that disappears before e/i, not appears — the sound /s/ is constant; only the spelling tool changes (ç before a/o, plain c before e/i). Other -çar verbs: almoçar (to have lunch), dançar (to dance), abraçar (to hug), começar.
Eu começo a trabalhar às oito da manhã.
I start work at eight in the morning.
Comecei a aprender português ano passado.
I started learning Portuguese last year.
A gente almoça por aqui todo dia.
We have lunch around here every day.
See the cedilha page for the full rule on when ç is needed.
Pattern 4: g → j before a/o
Soft-g verbs (in -ger and -gir) need the /ʒ/ sound. A plain g is soft only before e/i; before a or o it goes hard. To keep /ʒ/, the spelling switches to j, which is always /ʒ/.
Take proteger (to protect):
| Form | Spelling | Why |
|---|---|---|
| eu protejo (present) | protejo | before o, g → j to keep /ʒ/ |
| você protege | protege | before e, plain g is already soft /ʒ/ |
| que eu proteja (subjunctive) | proteja | before a, g → j to keep /ʒ/ |
Other verbs in this g→j group: eleger (to elect), dirigir (to drive), exigir (to demand), and fugir (to flee).
Eu protejo meus dados com senha forte.
I protect my data with a strong password.
Eu dirijo todo dia pra ir trabalhar.
I drive every day to get to work.
Pattern 5: gu → g before a/o
A rarer mirror image. Some verbs in -guir use gu to spell a hard /g/ before i (because plain g would be soft there). But before a or o, plain g is already hard — so the now-unneeded u drops out.
Take seguir (to follow):
| Form | Spelling | Why |
|---|---|---|
| eu sigo (present) | sigo | before o, plain g is already hard; drop the u |
| você segue | segue | before e, gu keeps the /g/ hard |
| que eu siga (subjunctive) | siga | before a, plain g is hard; no u needed |
(Seguir also has the e→i stem change — see the stem-changing -ir page — so it does double duty: the vowel raises and the u drops.)
Eu sigo todos os meus amigos no Instagram.
I follow all my friends on Instagram.
Siga em frente e vire à direita.
Go straight ahead and turn right.
The crucial point: nothing here is irregular
Every one of these verbs is a regular verb. The endings are the standard -ar, -er, -ir endings. Only the spelling of the consonant flexes, and it flexes by rule — never randomly. Contrast this with true stem changes, where the sound of the vowel actually changes. Here, the sound is frozen; the letters do all the moving.
Common Mistakes
❌ Eu ficei em casa ontem.
Incorrect — c before -ei goes soft /s/; you need qu to keep /k/: fiquei.
✅ Eu fiquei em casa ontem.
I stayed home yesterday.
❌ Eu chegei cedo.
Incorrect — g before -ei goes soft; you need gu: cheguei.
✅ Eu cheguei cedo.
I arrived early.
❌ Eu comeco às nove.
Incorrect — c before o is hard /k/; you need ç to keep /s/: começo.
✅ Eu começo às nove.
I start at nine.
❌ Eu protego as crianças.
Incorrect — a plain g before o would go hard /g/; proteger keeps /ʒ/, spelled with j: protejo.
✅ Eu protejo as crianças.
I protect the children.
❌ Eu sego a receita.
Incorrect — that reads as /s/; the eu form of seguir is sigo (with the e→i stem change too).
✅ Eu sigo a receita.
I follow the recipe.
Key Takeaways
- c → qu and g → gu before e/i keep a hard sound (ficar → fiquei, chegar → cheguei).
- c → ç and g → j before a/o keep a soft sound (começar → começo, proteger → protejo).
- gu → g before a/o drops a now-redundant u (seguir → sigo).
- These are spelling rules, not verb irregularities. The pronunciation is what stays constant.
Now practice Portuguese
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Start learning Portuguese→Related Topics
- Stem-Changing Verbs OverviewA2 — How and why the stem vowel shifts in certain Brazilian Portuguese verbs — and how that differs from purely spelling changes.
- The Cedilla (Ç)A1 — The cedilla makes 'c' sound like [s] before a, o, u — never before e or i, and never at the start of a word. How it shows up in -ção/-ança endings and why it drops in conjugation (começar → comece).
- SS vs S vs Ç vs C: When to Use Which for /S/A2 — The Brazilian Portuguese /s/ sound has six spellings — s, ss, ç, c, sc, x — and a single 's' between vowels is actually /z/, so position decides everything.
- Present Indicative: Regular -ar VerbsA1 — How to conjugate regular -ar verbs in the Brazilian Portuguese present indicative — plus the mandatory 'de' after gostar.