Learn Hardcore Portuguese (Brazil): Meu irmão corre rápido todas as manhãs no parque. - My brother runs fast every morning in the park.

In Brazilian Portuguese, possessives like meu, minha, meus, minhas are often used without the definite article, especially in speech:

Meu irmão – completely natural in Brazil.
O meu irmão – also correct, slightly more emphatic or formal, and more common in European Portuguese.

So both are grammatically correct; in Brazil, Meu irmão is the most usual everyday form.

Why is it corre and not está correndo, since this is a repeated action?

Portuguese normally uses the simple present (presente do indicativo) for habits and routines:

Meu irmão corre rápido todas as manhãs = He runs fast every morning (habit).
Meu irmão está correndo rápido = He is running fast (right now, at this moment).

So for something that happens regularly, corre is the natural choice, not está correndo.

Is rápido an adverb or an adjective here? Why not rapidamente?

In corre rápido, rápido functions as an adverb of manner (it tells us how he runs).

In Portuguese, many adjectives can also be used as adverbs without changing form, especially for speed and intensity:

Ele corre rápido. – He runs fast.
Ele fala alto. – He speaks loudly.

Rapidamente is also correct and more formal or “bookish”:

Meu irmão corre rapidamente todas as manhãs.

In everyday Brazilian speech, rápido is much more common than rapidamente in this kind of sentence.

If rápido is an adjective, shouldn’t it agree with irmão (masculine)? What happens with a feminine subject?

When rápido is used as an adverb, it does not change for gender or number:

Meu irmão corre rápido.
Minha irmã corre rápido. (not rápida)

When it is an adjective describing a noun, then it agrees:

Meu irmão é rápido. – My brother is fast.
Minha irmã é rápida. – My sister is fast.

So in your sentence, it stays rápido for any subject because it’s modifying the verb (corre), not the person.

Why is it todas as manhãs and not something like toda manhã or todas manhãs?

todas as manhãs = literally “all the mornings” → idiomatic for every morning.
- todas agrees in gender/number with manhãs (feminine plural).
- as is the required definite article in plural: todas as.

Other options:

toda manhã – also means “every morning”, very common and perfectly correct, a bit more informal/compact.
todas manhãs – sounds incorrect/unnatural; in standard Portuguese, you need the article: todas as manhãs.

So todas as manhãs is a standard, clear way to say “every morning”.

What exactly is no in no parque?

No is a contraction of the preposition em + the definite article o (masculine singular):

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

So no parque literally means em o parque (“in the park”), but the full form is almost never used; the contraction no is mandatory in normal Portuguese.

Could we say no parque todas as manhãs instead of todas as manhãs no parque? Does word order matter?

Both orders are grammatically correct. Common patterns:

Meu irmão corre rápido todas as manhãs no parque.
Meu irmão corre rápido no parque todas as manhãs.

Portuguese is flexible with adverbs of time (todas as manhãs) and place (no parque). The version you have is very natural: [verb] + [manner] + [time] + [place]. Changing the order can slightly change the rhythm or emphasis, but not the basic meaning.

Why is manhãs written with ã and ns but pronounced without an obvious final “s”?

ã marks a nasal vowel. In manhã, the nh plus tilde nasalize the vowel.
The plural manhãs adds an s, but in Brazilian Portuguese, final -s is often:
- pronounced like /s/ or /ʃ/ depending on region (e.g. Rio),
- or very soft/light in many accents.

So you clearly pronounce the nasal vowel ã and the nh sound; the s may be light but it is still there in careful speech: manhãs (plural) vs manhã (singular).

Why is irmão written with ão and an accent?

The ão ending indicates a nasalized sound and often marks a stressed final syllable. The accent (ã with tilde) shows:

The vowel is stressed: ir-MÃO.
The vowel is nasal.

Compare:

irmao – incorrect spelling.
irmão – correct; means “brother”.
The plural is irmãos (still nasal, still stressed on the last syllable).

Can the subject Meu irmão be omitted, like in Spanish?

Yes, Portuguese is also a pro-drop language, so the subject pronoun (and sometimes even a noun phrase) can be omitted when it’s clear from context. However:

Omitting a full noun like Meu irmão is less common unless it was mentioned right before.
Omitting pronouns is very common:
- Ele corre rápido todas as manhãs no parque.
- → After this, you might just say: Corre rápido todos os dias.

In isolation, you wouldn’t normally say only Corre rápido todas as manhãs no parque unless the subject is obvious from context.