Não importa se o curso é caro, eu quero aprender português.

Because importar has more than one meaning in Portuguese.

• importar = to import
• importar = to matter, to be important

In Não importa se..., it means it doesn’t matter whether/if...

This use is very common and often works like an impersonal expression:

• Não importa. = It doesn’t matter.
• O que importa é aprender. = What matters is learning.

So in this sentence, importa is about importance, not international trade.

Portuguese often uses importa impersonally, especially in expressions like não importa se...

So Não importa se o curso é caro is essentially:

• It doesn’t matter if the course is expensive

The it in English is just a dummy subject. Portuguese often does not need to express that kind of subject.

You could sometimes hear:

• Isso não importa. = That doesn’t matter.

But in this sentence, não importa se... is the more natural structure.

Here, se means if or whether.

So:

• Não importa se o curso é caro = It doesn’t matter if/whether the course is expensive

This is not the reflexive se, and it is not the same as si. It is the conjunction se used to introduce a condition or possibility.

Compare:

• Se chover, eu fico em casa. = If it rains, I’ll stay home.
• Não sei se ele vem. = I don’t know whether he is coming.

Portuguese uses definite articles much more often than English.

So o curso literally means the course, but in many contexts English would simply say the course or even just course, depending on the sentence.

In Portuguese, saying o curso sounds natural because you are talking about a specific course or the course under discussion.

Compare:

• O professor chegou. = The teacher arrived.
• A aula foi boa. = The class was good.

Leaving out the article here would usually sound unnatural.

Both ser and estar can sometimes be used with caro, but they give slightly different feelings.

• é caro = it is expensive, as a characteristic or general fact
• está caro = it is expensive right now, suggesting a temporary situation or current price condition

In your sentence, o curso é caro presents the price as a general quality of the course. That is why é caro works well.

Examples:

• Esse restaurante é caro. = That restaurant is expensive.
• A gasolina está cara. = Gas is expensive right now.

The comma separates the two parts of the sentence:

1. Não importa se o curso é caro
2. eu quero aprender português

The first part gives a condition or idea being dismissed, and the second part states the speaker’s real position.

In English, you would also often separate these ideas with a comma:

• It doesn’t matter if the course is expensive, I want to learn Portuguese.

In careful writing, some people might even prefer restructuring it with a stronger pause, but this comma is very normal in Portuguese.

That’s true: Portuguese often drops subject pronouns because the verb form already shows the person.

So you could say:

• quero aprender português

and it would still mean I want to learn Portuguese.

But eu is often included for:

• emphasis
• clarity
• contrast
• a more explicit or personal tone

In this sentence, eu quero aprender português can sound slightly more determined or emphatic: regardless of the price, I want to learn Portuguese.

When talking about languages after verbs like falar, aprender, estudar, and ensinar, Portuguese usually does not use an article.

So:

• aprender português = to learn Portuguese
• falar inglês = to speak English
• estudar espanhol = to study Spanish

Using an article here would usually sound unnatural in standard usage.

In Portuguese, names of languages and nationalities are normally not capitalized.

So:

• português
• inglês
• brasileiro
• americano

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

This is a very common structure in Portuguese:

• querer + infinitive

It means to want to do something.

So:

• quero aprender = I want to learn
• quero estudar = I want to study
• quero viajar = I want to travel

The first verb, quero, is conjugated. The second verb, aprender, stays in the infinitive.

Não is one of the most important words in Portuguese, and its pronunciation can be tricky.

In Brazilian Portuguese, it sounds roughly like:

• nowng
• or naw̃

Important points:

• The ão ending is nasal.
• It does not sound like a plain ow in English.
• Your air should resonate through the nose a bit.

A helpful comparison is that não rhymes approximately with the Brazilian pronunciation of words ending in -ão, like:

• mão
• pão
• irmão

In Brazil, quero is usually pronounced roughly like:

• KEH-roo or KEH-ro

The first syllable is stressed: QUE-ro.

A few notes:

• que here sounds like keh
• the r in the middle is not the strong English r
• the final o in Brazilian Portuguese often sounds closer to u in casual speech

So in natural Brazilian speech, quero may sound a bit like KEH-ru.

Normally, no. In this sentence, se is the natural choice.

Use:

• Não importa se o curso é caro.

That means:

• It doesn’t matter if/whether the course is expensive.

Using que after não importa would not be the standard structure for this meaning.

So a good rule is:

• não importa se... = it doesn’t matter if...
• não importa + noun/pronoun = it doesn’t matter

Examples:

• Não importa se está longe.
• Não importa o preço.

Yes. Portuguese allows some flexibility.

For example, you could say:

• Eu quero aprender português, não importa se o curso é caro.

This version puts the main desire first and the concessive idea second.

Both versions are natural, but the emphasis changes slightly:

• Não importa se o curso é caro, eu quero aprender português.
  The speaker begins by dismissing the obstacle.
• Eu quero aprender português, não importa se o curso é caro.
  The speaker begins with the goal.

Both are good Portuguese.