Relative pronouns
Relative pronouns glue two clauses into one sentence: 'the book' + 'I read it' → 'the book that I read'. Portuguese divides the work between four of them. que does almost everything — people, things, subject, object. quem is for people after a preposition. cujo means 'whose'. onde means 'where'. The one habit English speakers have to break: in Portuguese the relative pronoun is never left out.
que — the workhorse
que covers most relative clauses you'll ever build. It never changes shape, and it works for people and for things, as subject or as object. Subject: O homem que mora aqui é meu tio. Object: O livro que eu li ontem é ótimo. A person as object: A menina que eu vi na rua era a Inês. English lets you drop it — 'the book I read' — and Portuguese does not: o livro que eu li, always. If you find yourself with two verbs and nothing between them, you've probably swallowed a que.
quem — for people, after a preposition
quem is reserved for people, and in practice you meet it right after a preposition: com quem, de quem, a quem, para quem, por quem. A pessoa com quem eu falei era muito simpática. O amigo para quem eu dei o livro mora em Salvador. A cliente de quem eu te falei voltou hoje. Without a preposition, go back to que: a pessoa que eu vi, never a pessoa quem eu vi. In Brazil the preposition often softens to pra: o amigo pra quem eu dei o livro.
cujo — whose
cujo means 'whose', and here's the trick: it agrees with the thing OWNED, not with the owner. cujo (m. sg.), cuja (f. sg.), cujos (m. pl.), cujas (f. pl.). O escritor cujo livro eu li é brasileiro — livro is masculine singular, so cujo. A menina cuja mãe é médica chega amanhã — mãe is feminine, so cuja. Never put an article after it: cujo o livro is a mistake. cujo is bookish everywhere in Portuguese and especially rare in Brazilian speech, where people rebuild the sentence instead: o escritor que escreveu o livro que eu li. Learn it for reading, for writing, and for the day you want to sound sharp.
onde — where
onde points at a place: A cidade onde eu nasci é pequena. A padaria onde a gente se conheceu fechou. When motion is involved, careful writing uses aonde (to where) and de onde (from where): A cidade aonde vamos / A cidade de onde eu venho. In everyday Brazilian speech, plain onde covers all three, and it also leaks into time — you'll hear o dia onde eu te conheci. The textbook form for time is em que: o dia em que eu te conheci.
o qual — the formal alternative
There's also o qual / a qual / os quais / as quais, which agrees in gender and number with whatever it refers to. It earns its keep in two places: after a longer preposition, where que would sound cramped — a casa na qual eu morei, o motivo pelo qual eu liguei — and when a sentence has two possible antecedents and que would be ambiguous. Formal registers love it: contracts, journalism, academic writing. In speech, Brazilians say que and move on. Recognize it; you don't have to produce it yet.
How it really sounds in Brazil
The four pronouns are the same on both sides of the Atlantic; what differs is how loose the spoken language gets. que swallows the others: a pessoa que eu falei com ela is heard constantly, with a leftover ela propping up the sentence — non-standard, and useful to recognize rather than copy. cujo is almost absent from conversation. onde wanders into time and even into abstract 'in which'. And relative clauses in Brazil love the gerund alongside them: o cara que está lendo o jornal ali. Say que with confidence, keep quem for prepositions, and save cujo for when you're writing.
