Eu estudo português vinte minutos por dia.

Yes — in Brazilian Portuguese, eu is often optional here.

Because estudo already clearly means I study, you can say:

• Eu estudo português vinte minutos por dia.
• Estudo português vinte minutos por dia.

Both are natural.

Speakers include eu when they want to:

• emphasize I
• create contrast, as in Eu estudo português, mas ele estuda inglês
• make the sentence a little clearer in context

So eu is correct, but not required.

Estudo is the verb estudar conjugated for eu in the present tense.

• estudar = to study (infinitive)
• eu estudo = I study

This is the same kind of difference as:

• to speak vs I speak
• to live vs I live

So in the sentence, estudo is the form that matches eu.

In Portuguese, names of languages are normally not capitalized.

So you write:

• português
• inglês
• espanhol

This is different from English, where you write Portuguese, English, Spanish with capital letters.

So Eu estudo português... is the normal spelling.

After verbs like estudar, falar, aprender, and ensinar, the language usually appears without an article.

So you normally say:

• estudo português
• falo inglês
• aprendo japonês

Using o português is possible in some contexts, but it usually sounds less neutral or refers to the Portuguese language more explicitly as a noun. In a simple sentence like this, estudo português is the most natural choice.

Because vinte minutos expresses duration — how long the studying lasts.

Portuguese often places duration directly in the sentence without needing a preposition:

• Eu estudo português vinte minutos por dia.
• Eu trabalho oito horas por dia.
• Ela lê trinta minutos antes de dormir.

So vinte minutos works like for twenty minutes in English, even though Portuguese often does not need an equivalent of for there.

Yes, you can say:

• Eu estudo português por vinte minutos por dia.

That is also correct and understandable.

But Eu estudo português vinte minutos por dia is often more natural and direct. Portuguese commonly leaves out por when talking about duration.

So:

• vinte minutos por dia = very natural
• por vinte minutos por dia = also correct

Por dia means per day or a day, depending on how you translate it into natural English.

It is used for rates, frequency, or repeated amounts:

• vinte minutos por dia = twenty minutes per day
• duas vezes por semana = twice per week
• oito horas por noite = eight hours per night

In this sentence, por dia tells you that this amount happens each day.

Not exactly.

• vinte minutos por dia focuses on the daily amount
• todos os dias focuses on frequency: every day

Compare:

• Eu estudo português vinte minutos por dia.
  = I study Portuguese twenty minutes per day.

• Eu estudo português todos os dias.
  = I study Portuguese every day.

You can even combine them:

• Eu estudo português vinte minutos por dia, todos os dias.

That sounds a bit repetitive, but it is grammatically possible.

Because Portuguese often uses the simple present where English might use either the simple present or the present continuous.

• Eu estudo português... = I study Portuguese / I am studying Portuguese

If you say:

• Eu estou estudando português

that usually emphasizes that the action is happening right now or during the current period of your life.

In a general routine sentence like this one, Eu estudo português vinte minutos por dia is the most natural choice.

Yes, a little.

The most neutral order is:

• Eu estudo português vinte minutos por dia.

But you may also hear or use:

• Eu estudo vinte minutos de português por dia.
• Por dia, eu estudo português vinte minutos.

These are possible, but they are not all equally natural in every context.

A useful point:

• estudo português vinte minutos por dia = I study Portuguese for twenty minutes per day
• estudo vinte minutos de português por dia = also natural, with a slightly different structure

The original sentence is perfectly normal and clear.

The accent mark shows the stressed syllable and helps indicate pronunciation.

• português

The stress falls on the last syllable: -guês.

Without the accent, a reader might not know the correct stress pattern. Written accents in Portuguese are important because they help show:

• where the stress goes
• sometimes the vowel quality as well

So the accent in português is part of the correct spelling.

A common Brazilian pronunciation is approximately:

• por-too-GUES

with the stress on the last syllable.

A few notes:

• the r in por can vary by region
• the final s is usually pronounced like an s sound in Brazil
• the ê in guês is a stressed vowel

If you are just starting, the most important thing is to stress the last syllable:

• por-tu-GUÊS

Yes.

Português can mean:

• Portuguese (the language)
• Portuguese man / Portuguese person depending on context

Examples:

• Eu estudo português. = I study Portuguese.
• Ele é português. = He is Portuguese / He is a Portuguese man.

In your sentence, because it follows estudo, it clearly means the language.

Not in the same way.

For studying a subject, estudar is the normal verb:

• Eu estudo português.

Aprender means to learn, not to study:

• Eu aprendo português can sound less natural if you mean your study routine

A better sentence with aprender would be something like:

• Eu quero aprender português.
• Estou aprendendo português.

So for this sentence, estudo is the best choice.