Quanto mais eu estudo português, menos nervoso eu fico.

It’s a very common Portuguese pattern used to show a relationship like:

• the more ..., the less ...
• the more ..., the more ...
• the less ..., the more ...

So in:

Quanto mais eu estudo português, menos nervoso eu fico.

the structure means:

• Quanto mais eu estudo português = The more I study Portuguese
• menos nervoso eu fico = the less nervous I get / become

This is called a correlative comparative structure.

Yes, quanto often means how much or how many, but in this structure it has a different function.

In quanto mais ..., it does not mean how much by itself. Instead, the whole expression quanto mais means the more.

Some similar examples:

• Quanto mais eu leio, mais eu aprendo.
  The more I read, the more I learn.

• Quanto menos você dorme, mais cansado você fica.
  The less you sleep, the more tired you get.

So it’s best to learn quanto mais / quanto menos as fixed comparison patterns.

Portuguese expresses that idea differently. English says:

• the more
• the less

Portuguese uses:

• quanto mais
• quanto menos

So you should not try to translate word by word. The whole structure works as a unit.

Because each half of the sentence has its own clause, and each clause can have its own subject.

• Quanto mais eu estudo português
• menos nervoso eu fico

Portuguese often allows the subject pronoun to be omitted, because the verb ending already shows who is doing the action. So this sentence could also be:

Quanto mais estudo português, menos nervoso fico.

That sounds natural too.

The version with eu repeated is also perfectly correct. It can sound a bit clearer or slightly more emphatic.

Yes. That is also natural Portuguese.

You can say:

• menos nervoso eu fico
• menos fico nervoso

Both are acceptable.

The sentence you were given puts nervoso before the verb, which slightly highlights the result state: less nervous.

Compare:

• menos nervoso eu fico = emphasis on less nervous
• menos fico nervoso = emphasis on the whole verbal idea I get nervous less / I become less nervous

Both are good, and both are common.

Great question. Ficar often means to become, to get, or to end up being.

So:

• fico nervoso = I get nervous / I become nervous
• estou nervoso = I am nervous
• sou nervoso = I am a nervous person / I’m naturally nervous

In this sentence, the idea is about a change in state: as I study more, I become less nervous. That is why fico works very well.

So:

• menos nervoso eu fico = the less nervous I get

Using estou would sound more like a current state, and sou would sound like a personality trait.

Because nervoso is an adjective describing the subject eu.

• eu fico nervoso = I get nervous
• eu fico menos nervoso = I get less nervous

You are describing how I am / become, so you use an adjective.

Nervosamente means nervously, which is an adverb. That would describe how someone does something, not how someone feels or becomes.

For example:

• Ele falou nervosamente. = He spoke nervously.

But here we need an adjective, not an adverb.

Yes.

The adjective should agree with the speaker:

• male speaker: menos nervoso eu fico
• female speaker: menos nervosa eu fico

Because nervoso/nervosa agrees with eu, meaning the person speaking.

The comma separates the two linked clauses:

• Quanto mais eu estudo português,
• menos nervoso eu fico.

This is very common in Portuguese with this kind of the more..., the less... structure.

It helps readability and marks the pause between the two parts. In writing, the comma is usually expected here.

Yes, if the context already makes it clear what you are studying.

• Quanto mais eu estudo português, menos nervoso eu fico.
• Quanto mais eu estudo, menos nervoso eu fico.

The first is more specific. The second is more general or depends on context.

Usually, no.

In Portuguese, names of languages are normally written in lowercase:

• português
• inglês
• espanhol

So estudo português is correct.

This is different from English, where Portuguese must be capitalized.

Yes. Portuguese often drops subject pronouns when they are clear from the verb forms.

So this is very natural:

Quanto mais estudo português, menos nervoso fico.

This is also natural:

Quanto mais eu estudo português, menos nervoso eu fico.

The version without pronouns is a little more compact. The version with eu can sound more explicit or emphatic.

Yes. This structure is very productive in Portuguese. Some useful patterns are:

• Quanto mais..., mais... = The more..., the more...
• Quanto mais..., menos... = The more..., the less...
• Quanto menos..., mais... = The less..., the more...
• Quanto menos..., menos... = The less..., the less...

Examples:

• Quanto mais você pratica, melhor você fala.
  The more you practice, the better you speak.

• Quanto menos eu durmo, mais cansado eu fico.
  The less I sleep, the more tired I get.

• Quanto mais eu escuto português, mais natural ele parece.
  The more I listen to Portuguese, the more natural it seems.

This is a very useful pattern to learn early because it comes up often in real speech and writing.