Eu não quero correr esse risco hoje.

Yes. In Brazilian Portuguese, subject pronouns are often optional when the verb form already makes the subject clear.

• Eu não quero correr esse risco hoje = perfectly correct
• Não quero correr esse risco hoje = also very natural

Including eu can add emphasis, contrast, or clarity. For example, Eu não quero... may sound a bit more personally pointed, like I don’t want to.

In Portuguese, the normal negation pattern is:

não + verb

So:

• não quero = do not want
• não gosto = do not like
• não posso = cannot / am not able to

You do not usually place não after the verb the way some learners might expect from other languages.

After querer when you mean to want to do something, the next verb stays in the infinitive.

Pattern:

• querer + infinitive

So:

• quero correr = I want to run / I want to take
• quero comer = I want to eat
• quero sair = I want to leave

You would not say quero corro because corro is a conjugated form, and Portuguese does not use two fully conjugated verbs like that in this structure.

Yes. It is very close to English.

• correr um risco
• correr esse risco

both mean to take/run a risk

This is a common idiomatic expression in Portuguese. Even though correr usually means to run, in this expression it means to expose oneself to a risk.

In Brazilian Portuguese, esse is much more common than este in everyday speech.

Very roughly:

• este = this, nearer to the speaker
• esse = that, nearer to the listener or already mentioned
• aquele = that over there

But in real spoken Brazilian Portuguese, esse often covers cases where English would use either this or that.

So esse risco sounds completely natural.
Este risco is possible, but it may sound more formal, more careful, or less conversational.

Because demonstratives like esse, esta, aquele, and so on already work like determiners.

So you say:

• esse risco
• essa ideia
• aquele problema

not:

• o esse risco
• a essa ideia

In this sentence, esse already introduces the noun, so no article is needed.

Usually, correr esse risco is the most natural expression here.

Portuguese also has:

• assumir um risco = to assume a risk
• se arriscar = to take a chance / to risk oneself

But tomar esse risco is not the standard equivalent of English take that risk in this context. A native speaker would more naturally say:

• não quero correr esse risco
• não quero me arriscar
• não quero assumir esse risco

Yes, hoje can move around, but the version in the sentence is very natural.

Common possibilities:

• Eu não quero correr esse risco hoje.
• Hoje eu não quero correr esse risco.
• Eu hoje não quero correr esse risco.

The position changes the emphasis a little:

• ...hoje puts the time information at the end in a neutral way
• Hoje eu... emphasizes today
• Eu hoje... can sound slightly more contrastive, like as for today

A simple learner-friendly pronunciation is:

• quero ≈ KEH-roo or KEH-roh

More specifically in standard Brazilian pronunciation:

• que- sounds like keh
• -ro usually has a light tapped r between vowels, somewhat like the Spanish single r
• the final o is often pronounced more like u in many Brazilian accents, so it may sound closer to KEH-ru

So quero is often heard approximately as KEH-ru.

Not quite. A helpful approximation is:

• esse ≈ EH-see

But keep in mind:

• both s sounds are like English s, not z
• the first syllable is stressed: EH-see

In many Brazilian accents, the final e sounds like a short ee sound, which is why EH-see is a decent approximation for beginners.

Quero is the present tense of querer for eu.

Conjugation:

• eu quero = I want
• você quer = you want
• ele/ela quer = he/she wants
• nós queremos = we want
• vocês querem = you all want
• eles/elas querem = they want

Even though it is present tense, it works just like English I don’t want to... in this sentence.

It is neutral and very natural. It works well in both speech and writing.

Nothing in it is especially slangy or especially formal. You could say it:

• in conversation
• in a message
• in a more careful spoken context

If you wanted something more formal, you might choose a different wording, such as:

• Hoje, não desejo correr esse risco.

But that sounds more formal and less everyday than Eu não quero correr esse risco hoje.

Yes, but the meaning changes slightly.

• Eu não quero correr esse risco hoje = I do not want to take that/this specific risk today
• Eu não quero correr um risco hoje = I do not want to take a risk / any risk today

So:

• esse risco points to a specific, identifiable risk
• um risco is more general

No. With querer followed by another verb, you normally use the infinitive directly, with no preposition.

Correct:

• quero correr
• quero sair
• quero comer

Not:

• quero de correr
• quero pra correr

So the structure in the sentence is exactly what you want: quero + infinitive.

If you remove hoje, the sentence becomes more general:

• Eu não quero correr esse risco. = I do not want to take that risk.

With hoje, the speaker limits the statement to today:

• maybe they might take the risk another day
• but not today

So hoje adds a specific time frame rather than changing the core grammar.