Durante a reunião online, é melhor silenciar o microfone quando você não estiver falando.

Durante means during. It introduces a time expression, so Durante a reunião online means During the online meeting.

A few useful comparisons:

• durante a reunião = during the meeting
• antes da reunião = before the meeting
• depois da reunião = after the meeting

Here, durante is followed by the noun phrase a reunião online.

Because durante directly means during, so Portuguese usually says:

• durante a reunião = during the meeting

If you said na reunião, that would literally be more like in the meeting / at the meeting, which is a different structure.

Compare:

• Durante a reunião, todos ficaram em silêncio. = During the meeting, everyone stayed quiet.
• Na reunião, todos falaram sobre o projeto. = In/at the meeting, everyone talked about the project.

Both can be correct in different contexts, but this sentence specifically uses the during idea.

É melhor means it is better or it’s better.

It is a very common way in Portuguese to give advice or make a recommendation:

• É melhor esperar. = It’s better to wait.
• É melhor sair cedo. = It’s better to leave early.
• É melhor silenciar o microfone. = It’s better to mute the microphone.

It sounds natural and polite, not overly strong.

After é melhor, Portuguese often uses an infinitive verb to express a general action:

• É melhor estudar agora. = It’s better to study now.
• É melhor não falar. = It’s better not to speak.
• É melhor silenciar o microfone. = It’s better to mute the microphone.

This works a lot like English it’s better to...

Even though Portuguese does not always include a separate word for to, the infinitive already carries that idea.

Yes, it sounds natural and clear, especially in more neutral or careful Portuguese.

But in everyday speech, Brazilians may also say:

• deixar o microfone no mudo = leave the microphone on mute
• mutar o microfone = mute the microphone

That last one, mutar, is very common in informal tech-related speech, even though it comes from English.

So these are all possible:

• silenciar o microfone — neutral, clear
• colocar o microfone no mudo — very common
• mutar o microfone — informal and common in online contexts

Portuguese often uses definite articles more frequently than English.

So silenciar o microfone literally looks like mute the microphone, not mute microphone.

That is normal in Portuguese. With direct objects, the article is often expected:

• abrir a porta = open the door
• fechar a janela = close the window
• silenciar o microfone = mute the microphone

Even when English might sound more general, Portuguese often still uses o / a / os / as.

This is one of the most important grammar points in the sentence.

After quando, Portuguese often uses the future subjunctive when talking about something that will happen or whenever something happens in the future.

So:

• quando você não estiver falando = when you are not speaking / when you’re not going to be speaking

This is about a future situation during the meeting, not about what is happening right now.

If you say:

• quando você não está falando

that sounds more like a habitual or descriptive statement, and in this kind of advice sentence, Brazilian Portuguese normally prefers estiver.

Estiver is the future subjunctive of estar.

Here is the relevant part of estar in the future subjunctive:

• quando eu estiver
• quando você estiver
• quando ele/ela estiver
• quando nós estivermos
• quando vocês estiverem
• quando eles/elas estiverem

This tense is very common after words like:

• quando = when
• se = if
• assim que = as soon as
• logo que = as soon as

Examples:

• Quando eu chegar, te aviso. = When I arrive, I’ll let you know.
• Se você puder, me liga. = If you can, call me.
• Quando você não estiver falando, silencie o microfone. = When you’re not speaking, mute the microphone.

Estiver falando is a continuous form: be speaking.

So:

• quando você não estiver falando = when you are not speaking

This emphasizes the ongoing action of speaking.

If you said:

• quando você não falar

that would sound less natural here, because it can suggest when you do not speak in a more abstract or event-based way.

In an online meeting, the point is whether you are actively speaking at that moment, so estiver falando is very natural.

In Brazilian Portuguese, você is often included because it sounds natural and helps clarity.

So this sentence could be:

• ...quando você não estiver falando.

That is perfectly normal.

You could also omit it:

• ...quando não estiver falando.

This can still be understood from context, but Brazilian Portuguese often prefers to state the subject pronoun more than European Portuguese does.

So including você is completely natural.

Yes, in some regions of Brazil, tu is common. But the verb forms vary by region.

Standard grammar would suggest:

• quando tu não estiveres falando

However, in many parts of Brazil, people use tu with verb forms closer to você speech, especially informally.

For a learner, você is usually the safest and most widely understood choice in Brazil:

• quando você não estiver falando

Yes, online is very common in Brazilian Portuguese, especially in technology, work, and education contexts.

So reunião online sounds completely natural.

You may also hear:

• reunião virtual = virtual meeting
• reunião por vídeo = video meeting
• videoconferência = videoconference

But reunião online is modern, common, and easy to understand.

The phrase Durante a reunião online is an introductory time expression.

In Portuguese, a comma after an introductory phrase like that is very common and helps readability:

• Durante a reunião online, é melhor silenciar o microfone...

Without the comma, the sentence could still be understood, but the comma makes it flow more clearly.

This is similar to English:

• During the online meeting, it’s better to mute the microphone...

Reunião can be tricky for English speakers.

A rough guide is:

• reu sounds somewhat like reh-oo blended together
• ni sounds like nee
• ão is a nasal sound, something like owng said through the nose, but not exactly

The stress is on the last syllable:

• reu-ni-ÃO

A rough approximation is heh-oo-nee-OWN with a nasal ending, but that is only approximate.

The hardest part is -ão, which is a very common Brazilian Portuguese ending:

• reunião
• situação
• informação

Yes. That would be a very natural alternative in everyday Brazilian Portuguese.

Compare:

• É melhor silenciar o microfone... — slightly more neutral/formal
• É melhor deixar o microfone no mudo... — very common in speech
• É melhor mutar o microfone... — informal, tech-style speech

All three communicate basically the same idea. The original sentence is a good choice because it is clear and standard.

It breaks down like this:

• Durante a reunião online = during the online meeting
• é melhor = it is better
• silenciar o microfone = to mute the microphone
• quando você não estiver falando = when you are not speaking

So the pattern is:

Time expression + recommendation + action + condition

That structure is very common in Portuguese for giving advice.