Regular –IR verbs

Don't let the small size fool you — -IR verbs punch above their weight in daily Brazilian life. You can't go anywhere without partir or sair, you can't open doors or windows without abrir, you can't share the bill or a cake without dividir, and you can't make plans without decidir. These verbs show up in everyday moments: Que horas você parte? (What time are you leaving?), Você divide o apartamento? (Do you share the apartment?), A gente divide a conta? (Shall we split the bill?).

On top of that, finishing -IR rounds out all three Portuguese regular conjugations. From here, every regular verb you meet — and most modern loanwords land on -AR by default — falls into a pattern you already know.

The -IR Conjugation Pattern

The -IR conjugation is the close cousin of the -ER conjugation — for the common Brazilian pronouns shown here, the written endings are almost identical except for one detail in the nós form. Once you know -ER, -IR takes minutes, not hours.

Use PARTIR (to leave / to break) as the model:

1. Find the stem: PARTIR − IR = PART-

2. Add the ending that matches the subject:

EU → -O

• part + o = parto (I leave)

TU → -ES (standard agreement; use and agreement vary by region in Brazil)

Daily Life

• "Eu abro a porta de manhã" (I open the door in the morning)

• "Você divide o apartamento?" (Do you share the apartment?)

• "A que horas vocês partem?" (What time are you leaving?)

• "Ela assiste televisão todo dia" (She watches TV every day)

• "Nós dividimos o bolo" (We share the cake)

Decisions & Plans

• "Eu decido depois" (I'll decide later)

• "A gente decide isso agora" (We decide this now)

• "Vocês permitem cachorro?" (Do you allow dogs?)

• "Ele descobre tudo" (He finds out everything)

The dormir family

In the present indicative, the written stem vowel changes o → u only in the eu form:

• dormir → eu durmo

• cobrir → eu cubro

• descobrir → eu descubro

• tossir → eu tusso

SUBIR (to go up) follows a different pattern: subo, sobes, sobe, subimos, sobem. In the present indicative, the written vowel changes u → o with tu, você/ele/ela/a gente and vocês/eles/elas; eu and nós keep u.

False friends if you also speak Spanish

Compare Portuguese -IR verbs with their Spanish look-alikes:

• assistir = to watch / attend; it can also mean to help or assist. Spanish asistir can mean both to attend and to help.

The two related meanings of partir

Partir descends from Latin partīre "to share, divide" — the same root that gave English part, party, particle and apartment. The "break / cut" sense kept the original meaning of splitting something into pieces, while the "depart" sense came from the metaphor of separating yourself from a place. That is why partir o bolo (cut the cake) and partir para o aeroporto (leave for the airport) are the same verb doing two related jobs.

Source: Wiktionary — partir (Portuguese etymology).

The -IR class is two Latin conjugations rolled into one

Classical Latin had four regular conjugations; Portuguese trimmed it down to three by rerouting the inheritance. Most modern -IR verbs descend from Latin's 4th conjugation in -īre (partīre → partir, aperīre → abrir), and a smaller set are refugees from the 3rd conjugation in short -ere (dīvidere → dividir). Despite their different origins, these regular verbs now share the -IR pattern.