Eu preciso lembrar de desligar o celular antes da reunião.

Yes — Portuguese often allows you to omit the subject pronoun when the verb form already makes the subject clear.

So:

• Eu preciso lembrar de desligar o celular antes da reunião.
• Preciso lembrar de desligar o celular antes da reunião.

Both are correct.

Including eu can:

• add emphasis
• make the subject extra clear
• sound a little more explicit in conversation

In many everyday situations, Preciso lembrar... is the more natural version.

Because the sentence expresses necessity plus the action of remembering.

• preciso = I need
• lembrar = to remember

So the structure is basically:

• Eu preciso lembrar de...
• I need to remember to...

This is very similar to English, where you also use two verbs:

• I need
• to remember
• to turn off...

Portuguese just builds it a little differently with lembrar de + infinitive.

Because lembrar often takes the preposition de when followed by a noun or another verb.

So you get:

• lembrar de algo = to remember something
• lembrar de fazer algo = to remember to do something

Examples:

• Lembrei da chave. = I remembered the key.
• Lembrei de levar a chave. = I remembered to bring the key.

This is an important pattern to memorize:

• lembrar de + infinitive

In everyday Brazilian Portuguese, this is very common.

Both can mean to remember.

Examples:

• Eu lembro de desligar o celular.
• Eu me lembro de desligar o celular.

Both are used in Brazil. In casual speech, many speakers prefer simpler forms like:

• Eu lembro
• Eu lembrei
• Preciso lembrar

The version with -se can sound a little more formal or careful depending on context:

• Eu me lembro daquilo. = I remember that.

For a learner, the key point is:

• lembrar de + noun/verb is common
• lembrar-se de + noun/verb is also correct

Because after lembrar de, Portuguese uses the infinitive to express the action that needs to be remembered.

So:

• lembrar de desligar
• remember to turn off

This is similar to English to turn off.

Other examples:

• Preciso lembrar de ligar para ela. = I need to remember to call her.
• Ele lembrou de fechar a porta. = He remembered to close the door.

So the pattern is:

• lembrar de + infinitive verb

Because desligar is the normal verb for turn off electronic devices.

• desligar o celular = turn off the phone
• desligar a TV = turn off the TV
• desligar o computador = turn off the computer

Other verbs mean different things:

• fechar = to close
• apagar = to erase, delete, or switch off a light in some contexts
• silenciar = to silence / put on silent

So:

• desligar o celular = turn the phone off completely
• silenciar o celular = silence the phone

Portuguese often uses the definite article where English might use a possessive.

So if it is obvious whose phone we are talking about, Brazilian Portuguese may simply say:

• desligar o celular

Even though English would often say:

• turn off my phone

Both are possible in Portuguese:

• desligar o celular
• desligar meu celular

The version with o celular sounds perfectly natural when the ownership is already understood.

In Brazilian Portuguese, celular means cell phone / mobile phone.

Examples:

• Onde está meu celular? = Where is my phone?
• Esqueci o celular em casa. = I forgot my phone at home.

If you know European Portuguese, note that telemóvel is more common there. In Brazil, celular is the normal word.

Because antes normally appears with de when followed by a noun phrase:

• antes de + noun
• antes de + verb

Here, a reunião has the feminine article a. So:

• antes de + a reunião → antes da reunião

This is a contraction:

• de + a = da

Examples:

• antes da aula = before class
• antes do almoço = before lunch
• antes de sair = before leaving

So da is just de + a combined.

Yes. Portuguese word order is flexible here.

These are all natural:

• Eu preciso lembrar de desligar o celular antes da reunião.
• Antes da reunião, eu preciso lembrar de desligar o celular.
• Eu preciso, antes da reunião, lembrar de desligar o celular.

The most neutral and common version is the original one, with antes da reunião at the end.

Putting it first can add focus:

• Antes da reunião... = Before the meeting...

It is natural and correct. A Brazilian would understand it immediately.

Some very common everyday alternatives are:

• Preciso lembrar de desligar o celular antes da reunião.
• Tenho que lembrar de desligar o celular antes da reunião.

Difference in tone:

• preciso = I need to
• tenho que = I have to / need to

Both are common in speech. The version without eu often sounds a little more natural in casual conversation.

Reunião can be tricky because of the stress and the nasal ending.

A rough guide is:

• re-u-ni-ÃO

The stress is on the last syllable:

• ão

That final ão is nasal, which is a very common Brazilian Portuguese sound.

A rough English approximation is something like:

• heh-oo-nee-OW̃

But the final part should be nasal, not a plain English ow.

Also note that:

• reunião = meeting
• plural: reuniões

No. In this sentence, lembrar de desligar means remember to turn off.

That is, the turning off happens after the remembering.

So the meaning is:

• First: remember
• Then: turn off the phone
• Time reference: before the meeting

If you wanted to talk about remembering a past action, Portuguese would usually be phrased differently, for example:

• Lembro que desliguei o celular antes da reunião.
• I remember that I turned off the phone before the meeting.

So lembrar de + infinitive usually points to remembering to do something.

Yes. This sentence pattern is very useful.

You can swap in many other time expressions:

• antes da aula = before class
• antes do trabalho = before work
• antes do jantar = before dinner
• antes da viagem = before the trip

Examples:

• Preciso lembrar de desligar o celular antes da aula.
• Preciso lembrar de mandar a mensagem antes do trabalho.

So the full pattern is:

• Preciso lembrar de + infinitive + antes de/do/da + noun