Antes de jantarmos, eu vou passar na padaria para comprar pão.

Jantarmos is the personal infinitive, a form that Portuguese uses to show who is doing the action while still keeping an infinitive structure.

• jantar = to have dinner
• jantamos = we have dinner / we eat dinner
• jantarmos = for us to have dinner / we have dinner in a structure like antes de

So antes de jantarmos means before we have dinner.

The personal infinitive is a feature of Portuguese that English does not really have. It is an infinitive that changes form depending on the subject.

With jantar, the personal infinitive forms are:

• jantar = for me/you/him/her to have dinner
• jantarmos = for us to have dinner
• jantarem = for them/you all to have dinner

In this sentence, Portuguese uses jantarmos to make it clear that the subject is we.

Because antes de + infinitive is a very common Portuguese structure.

So:

• antes de jantarmos = before we have dinner
• antes de sair = before leaving
• antes de comprar pão = before buying bread

This is just the normal pattern with antes when it is followed by an infinitive form.

Yes, that is possible, but it is a different structure.

• antes de jantarmos uses the infinitive
• antes que jantemos uses the subjunctive

Both can mean the same thing, but antes de + infinitive is often the more straightforward and common choice here. Antes que jantemos can sound a bit more formal or more literary depending on the context.

Because the two clauses have different subjects.

• jantarmos = we have dinner
• eu vou passar = I am going to stop by

So the full idea is: Before we have dinner, I’m going to stop by the bakery to buy bread.

That mix of subjects is completely normal.

No, not strictly.

Portuguese often drops subject pronouns because the verb ending already shows the person:

• eu vou
• tu vais
• ele/ela vai

So Vou passar na padaria para comprar pão would also be natural.

Including eu can add:

• emphasis
• contrast
• extra clarity

For example, it might suggest I’ll do it rather than someone else.

Because ir + infinitive is a very common way to talk about the future in Portuguese, especially in everyday speech.

• vou passar = I’m going to stop by / I will stop by
• passarei = I will stop by

Both are correct, but vou passar sounds more natural in normal conversation. This is true in European Portuguese too.

Here passar does not mean literally to pass in the English sense. In this kind of sentence, passar na padaria means:

• to stop by the bakery
• to pop into the bakery
• to drop by the bakery

It often suggests a brief visit, sometimes on the way somewhere else.

Na is a contraction:

• em + a = na

Since padaria is a feminine singular noun, Portuguese combines the preposition and the article:

• em a padaria → na padaria

So passar na padaria is the natural form.

Yes, you could, but the nuance is a little different.

• vou à padaria = I’m going to the bakery
• vou passar na padaria = I’m stopping by the bakery

The second version often sounds more like a quick errand or a brief stop.

Para + infinitive is used to express purpose.

So:

• para comprar pão = to buy bread / in order to buy bread

It explains why the speaker is stopping by the bakery.

In European Portuguese speech, para is often pronounced in a reduced way, something like p'ra, but the normal spelling is still para.

Because pão is being used in a general, non-specific way.

• comprar pão = buy bread
• comprar o pão = buy the bread, meaning some specific bread already known in the conversation

So in this sentence, pão means bread in general, not a particular loaf already identified.

Yes, sometimes it could, but it is less explicit.

• antes de jantar = before having dinner / before dinner
• antes de jantarmos = before we have dinner

The version with jantarmos clearly tells you the subject is we. That is why it is especially useful when the speaker wants to be precise.

Because Antes de jantarmos is an introductory time clause.

In standard writing, when this kind of clause comes first, it is normally separated from the main clause with a comma:

• Antes de jantarmos, eu vou passar na padaria...

It helps make the structure of the sentence clearer.