Todos os amigos vão ao cinema.

Todos os amigos literally means all the friends.

• todos = all / every (plural)
• os = the (masculine plural definite article)
• amigos = friends (masculine plural)

In Portuguese, you normally keep the article with the noun, even after todos:

• todos os amigos = all the friends
• todas as casas = all the houses

Leaving out the article often sounds wrong or very unnatural in this kind of phrase.

No, not in standard European Portuguese. Todos amigos sounds wrong.

You need the article:

• ✅ Todos os amigos vão ao cinema.
• ❌ Todos amigos vão ao cinema.

In Portuguese, when todos/todas is followed by a noun, you almost always use the definite article in between: todos os, todas as, todos os alunos, etc.

vão comes from the verb ir (to go).

In this sentence, vão is:

• tense: present indicative
• person/number: 3rd person plural (they)

Present tense of ir:

• eu vou – I go / I am going
• tu vais – you go (informal singular)
• ele / ela / você vai – he / she / you (formal) goes
• nós vamos – we go
• vocês vão – you (plural) go
• eles / elas vão – they go

Here, vão matches os amigos (they).

In Portuguese, the present indicative can express both:

• a general/habitual action:
  
  • Todos os amigos vão ao cinema aos sábados.
    → All the friends go to the cinema on Saturdays.
• a near-future or arranged action (similar to English are going):
  
  • Todos os amigos vão ao cinema amanhã.
    → All the friends are going to the cinema tomorrow.

So Todos os amigos vão ao cinema can be understood as go or are going, depending on context.

ao is a contraction of the preposition a (to) + the article o (the, masculine singular):

• a + o = ao

So ao cinema literally means to the cinema.

This contraction is compulsory in standard Portuguese whenever a meets o:

• Vou ao parque. (a + o parque)
• Ela vai ao médico. (a + o médico)

All three forms exist, but they are not the same:

• ao cinema = to the cinema, focusing on the destination (movement)
  
  • ir ao cinema = go to the cinema
• para o cinema = also to the cinema, often a bit more goal‑oriented or neutral; in many contexts it overlaps with ao cinema
• no cinema = in/at the cinema, using em + o → no
  
  • Estou no cinema. = I am at the cinema.

For the fixed expression go to the movies, European Portuguese most often uses ir ao cinema.

cinema is a masculine noun.

You can see this from:

• the article in the sentence: ao cinema = a + o cinema
• other forms you might hear:
  • o cinema – the cinema
  • um cinema – a cinema
  • no cinema – at the cinema (em + o)

Masculine nouns typically use o / um, feminine ones use a / uma.

Yes.

• Todos os amigos vão ao cinema. = All the friends are going to the cinema.
• Todos vão ao cinema. = They all are going to the cinema.

In the second sentence, os amigos is understood from context (you already know who they are). Portuguese allows you to drop the noun when the group is clear: Todos vão, Todos chegam, etc.

Both are grammatically correct, but the usual, neutral form is:

• Todos os amigos vão ao cinema.

Os amigos todos vão ao cinema is also possible, but it tends to sound more emphatic or colloquial, like stressing the friends, all of them. In everyday, neutral speech, Todos os amigos is preferred.

You add meus (my) before amigos:

• Todos os meus amigos vão ao cinema.

Structure:

• todos – all
• os – the (matches amigos)
• meus – my (masculine plural, agrees with amigos)
• amigos – friends

The order is: todos + article + possessive + noun → Todos os meus amigos.

Approximate European Portuguese pronunciation:

• vão: /vɐ̃w̃/
  
  • v like English v
  • ão is a nasal sound, similar to the end of English own, but nasalized
• cinema: /siˈnɛmɐ/
  
  • ci = see
  • stress on ne: si-NE-ma
  • final a is reduced, like a very short uh

So the sentence sounds roughly like: TO-dush uz ɐ-MI-gush vɐ̃w̃ aw si-NE-mɐ (very approximate).

Yes, Todos os amigos vão ao cinema is correct in both European and Brazilian Portuguese.

Differences are mainly:

• Pronunciation: Brazilians open vowels more and pronounce most final vowels clearly (e.g. cinema closer to /siˈnemɐ/).
• Alternatives: In Brazil, you might also hear Todos os amigos vão para o cinema more often, but vão ao cinema is still perfectly fine and widely understood.