A colega cuja irmã trabalha na padaria trouxe-nos torradas e croissants.

Colega is a noun that can refer to either a man or a woman. The word itself stays the same; the article shows the gender:

• A colega = the female colleague
• O colega = the male colleague

So in this sentence, A tells you the colleague is female.

Cuja means whose.

It is a possessive relative word that links a colega and irmã:

• a colega
• a irmã da colega

Instead of repeating that idea more explicitly, Portuguese uses cuja:

• A colega cuja irmã... = The colleague whose sister...

After cujo / cuja / cujos / cujas, Portuguese normally does not use an article.

So you say:

• cuja irmã
• not cuja a irmã

This is one of the special rules of cujo. English speakers often want to insert an article because English uses whose sister, but Portuguese just uses cuja irmã directly.

Because cujo changes to match the thing possessed, not the owner.

Here, the possessed thing is irmã, which is:

• feminine
• singular

So the correct form is cuja.

The full set is:

• cujo = masculine singular
• cuja = feminine singular
• cujos = masculine plural
• cujas = feminine plural

Examples:

• o homem cujo carro...
• a mulher cuja irmã...
• os alunos cujos livros...
• as meninas cujas mochilas...

Because this is a restrictive relative clause: it identifies which colleague we mean.

• A colega cuja irmã trabalha na padaria... = the colleague whose sister works at the bakery

The clause helps define the noun, so normally there is no comma.

If you added commas, it would sound more like extra, non-essential information:

• A colega, cuja irmã trabalha na padaria, ...

That changes the feel of the sentence and is less neutral here.

Because the sentence combines:

• an ongoing/general fact: the sister works at the bakery
• a completed past action: the colleague brought us toast and croissants

So:

• trabalha = present, because this is presented as a current fact
• trouxe = preterite, because the bringing happened at a specific time in the past

If the sister used to work there but no longer does, Portuguese might use trabalhava instead.

Trouxe is the preterite of trazer.

• infinitive: trazer = to bring
• preterite: trouxe = brought

It is an irregular verb. Some key forms are:

• eu trouxe
• tu trouxeste
• ele/ela trouxe
• nós trouxemos
• vocês/eles trouxeram

In this sentence, trouxe means the action was completed in the past.

In European Portuguese, in a normal affirmative main clause, object pronouns often come after the verb, attached with a hyphen. This is called enclisis.

So:

• trouxe-nos = brought us

This is very typical of Portugal Portuguese.

In Brazilian Portuguese, nos trouxe is much more common.

In European Portuguese, the pronoun moves before the verb in certain situations, for example after negation:

• Não nos trouxe torradas.

Here nos means to us or for us.

In this sentence:

• trouxe-nos torradas e croissants

the things being brought are torradas e croissants, and nos refers to the people who received them.

So the structure is roughly:

• someone brought something
• to us

Na is a contraction of:

• em
  • a = na

So:

• na padaria = in/at the bakery

This kind of contraction is very common in Portuguese:

• no = em + o
• na = em + a
• nos = em + os
• nas = em + as

It can mean either in the bakery or at the bakery, depending on context.

With trabalhar, English often prefers at:

• works at the bakery

But Portuguese uses em very naturally in situations where English may choose in or at.

So na padaria is completely normal here.

Because the sentence is talking about some toast and croissants, not a specific already-known set.

So:

• trouxe-nos torradas e croissants

sounds like she brought us some toast and croissants.

If you used articles:

• trouxe-nos as torradas e os croissants

that would sound more like specific toast and croissants already identified in the conversation.

Yes. Croissant is a very common borrowed word in Portuguese, especially in Portugal, and croissants is a normal plural form in writing.

So this part of the sentence is perfectly natural.

A useful breakdown is:

• A colega cuja irmã trabalha na padaria = the subject
• trouxe-nos = the verb + pronoun
• torradas e croissants = the thing brought

More specifically:

• A colega = main noun
• cuja irmã trabalha na padaria = relative clause describing that colleague
• trouxe = main verb
• nos = recipient
• torradas e croissants = direct object

So the sentence is built around a subject with a descriptive clause, followed by the main action.

The main difference would usually be pronoun placement.

European Portuguese:

• A colega cuja irmã trabalha na padaria trouxe-nos torradas e croissants.

Brazilian Portuguese would more naturally say:

• A colega cuja irmã trabalha na padaria nos trouxe torradas e croissants.

The grammar is very similar, but the position of nos is one of the clearest differences.