A ação começa agora.

Because ação is a noun, and Portuguese very often uses a definite article where English may or may not use the.

Here, a is the feminine singular form of the:

• o = masculine singular
• a = feminine singular
• os = masculine plural
• as = feminine plural

So a ação is the action.

In Portuguese, leaving out the article can sound unnatural in many normal sentences. Ação começa agora would sound much less standard than A ação começa agora.

Because nouns in Portuguese have grammatical gender, and ação is a feminine noun.

That means it takes feminine words with it:

• a ação
• esta ação
• uma ação importante

A useful pattern: many nouns ending in -ção are feminine:

• a informação
• a situação
• a estação
• a decisão

So once you see -ção, it is a good clue that the noun is feminine.

A rough pronunciation is ah-SOWN, but with a nasal ending.

A few important parts:

• ç sounds like s
• ã/ão is nasal, so the sound comes partly through the nose
• the stress is on the last syllable: a-ÇÃO

So:

• ação ≈ ah-SOWN (nasal)
• not like an English sh sound
• not like a hard k sound

In Brazilian Portuguese, ão is a very common nasal ending:

• não
• pão
• oração
• ação

The cedilla, ç, makes the letter c sound like s.

So:

• ação = a-são
• começa = ko-ME-sa

Without the cedilla, the pronunciation would change before a, o, or u:

• ca, co, cu normally have a hard k sound
• ça, ço, çu have an s sound

That is why the verb appears as começa and not comeca.

Começa comes from the verb começar, which means to begin or to start.

This is the third-person singular form in the present tense:

• eu começo
• você começa
• ele/ela começa
• a ação começa

Since a ação is singular, the verb is singular too: começa.

Portuguese often uses the present tense for things happening now or starting now, just like English can do in sentences such as:

• The show starts now
• The game begins now

So A ação começa agora is completely natural in the present tense. It describes something beginning at this moment.

The accent mark in ação helps show the stressed syllable and is part of the correct spelling.

The stress falls on the last syllable:

• a-ÇÃO

In Portuguese, accents are not optional decoration. They are part of the written language and can:

• show stress
• distinguish words
• sometimes help indicate vowel quality

So you should always write ação, not acao.

A good approximation is ko-MEH-sa.

Breakdown:

• co = ko
• me = meh
• ça = sa

Stress is on the middle syllable:

• co-ME-ça

So the whole sentence has this rhythm:

• A a-ÇÃO co-ME-ça a-GO-ra

Yes. Agora is flexible.

The most neutral version here is:

• A ação começa agora.

But you could also say:

• Agora a ação começa.

That version puts more focus on now.

In many cases, both are correct, but the emphasis changes:

• A ação começa agora = neutral statement
• Agora a ação começa = now is highlighted

They are similar, but começar is usually more common and more everyday.

Both can mean to begin / to start:

• A aula começa às oito.
• A aula se inicia às oito.

But iniciar can sound a bit more formal or less conversational in some contexts.

For a natural, common sentence like this, começa is a very good choice.

Yes, and it changes the feel slightly.

• A ação começa agora = The action starts now / begins now
• A ação está começando agora = The action is starting now

The version with está começando emphasizes the action as a process already getting underway. The simple present começa sounds a bit more direct and slogan-like.

Yes. It sounds natural, especially in contexts like:

• movies
• sports
• promotions
• dramatic narration
• advertising

It has a strong, punchy feel, like announcing that the exciting part begins now.

So it is grammatically normal and also stylistically useful.

The main stress pattern is:

• A a-ÇÃO co-ME-ça a-GO-ra

More specifically:

• ação → stress on ÇÃO
• começa → stress on ME
• agora → stress on GO

Getting the stress right will make your Portuguese sound much more natural, even if your accent is still English-influenced.