Learn Hardcore Portuguese (Brazil): Quando todos confirmarem presença, a tarefa ficará mais tranquila. - When everyone confirms attendance, the task will become smoother.

Because in Portuguese a quando clause referring to a specific future event requires the future subjunctive. Confirmarem is the 3rd-person plural future subjunctive of confirmar. Using confirmam (present indicative) would imply a habitual or general action (“whenever everyone confirms”) rather than a one-time future condition.

Can I say Quando todos confirmam presença, and what’s the nuance?

You can, but it changes the meaning. Quando todos confirmam presença (present indicative) suggests a repeated or habitual situation (“whenever everyone confirms”). To talk about one specific upcoming event, use the future subjunctive confirmarem to signal an action that hasn’t happened yet.

Why isn’t there an article before presença? Could it be confirmar a presença?

In Brazilian Portuguese, confirmar presença (no article) is a fixed expression meaning to RSVP or to confirm attendance. You can add an article (confirmar a presença), but omitting it is more idiomatic and concise.

What exactly does quando function as in this sentence?

Quando is a subordinating conjunction meaning when, introducing a temporal clause. It sets the condition or point in time (“when everyone confirms attendance”) for the action of the main clause.

Why use ficará instead of the periphrastic future vai ficar?

Ficará is the synthetic (simple) future of ficar, and it’s perfectly correct and somewhat more formal. Vai ficar is the analytic or periphrastic future (colloquial) and also acceptable: vai ficar mais tranquila.

What does mais tranquila mean, and why is it feminine singular?

Mais tranquila means more calm or easier (in context). Adjectives in Portuguese agree with the noun they modify in gender and number. Tarefa is feminine singular, so the adjective takes the feminine singular form tranquila, with mais indicating the comparative “more.”

Could I use será mais tranquila instead of ficará mais tranquila?

You could, but there’s a nuance. Ficar often emphasizes a change of state (“will become calmer/easier”), whereas ser is more neutral and describes a quality. Both are grammatically correct, though ficar is idiomatic for expressing the resulting state.

What role does todos play here, and why not todas or todas as pessoas?

Todos is an indefinite pronoun meaning everyone (masculine generic). It covers all the people involved. You could say todas as pessoas, but todos is shorter and equally understood as “all of them.”