Quero cantar o dueto, só que o microfone não funciona.

In Brazilian Portuguese, subject pronouns are often omitted when the verb form already makes the subject clear. Quero means I want, so eu is not necessary.

• Quero = I want
• Eu quero = I want too, but with extra emphasis or clarity

Both are correct. Leaving out eu sounds very natural in everyday Portuguese.

After querer when you want to say want to do something, Portuguese uses the infinitive form of the next verb.

So:

• Quero cantar = I want to sing
• Quero comer = I want to eat
• Quero sair = I want to leave/go out

This is similar to English want + to + verb, except Portuguese does not need a separate word like to here. The infinitive itself does the job.

Portuguese often uses the definite article more than English does. In this sentence, o dueto means the duet.

Using the article makes it sound like a specific duet, not just duet singing in general.

• cantar o dueto = sing the duet
• cantar um dueto = sing a duet

If the speaker has a particular duet in mind, o dueto makes sense.

Só que is a very common Brazilian Portuguese expression meaning something like:

• but
• except that
• the thing is
• only

In this sentence, it introduces a problem or contrast:

• Quero cantar o dueto, só que o microfone não funciona.
• I want to sing the duet, but the microphone doesn’t work.

In spoken Brazilian Portuguese, só que is extremely natural and common.

They are similar, but not always identical in tone.

• mas = standard but
• só que = often a little more conversational, like but the thing is...

Compare:

• Quero cantar o dueto, mas o microfone não funciona.
• Quero cantar o dueto, só que o microfone não funciona.

Both are correct. The version with só que can sound a bit more informal and speech-like in Brazilian Portuguese.

Microfone is a masculine noun, so it takes o:

• o microfone = the microphone

There is no perfect rule that lets you always predict noun gender, so in many cases you simply learn the noun together with its article.

A useful habit is to memorize nouns as a unit:

• o microfone
• a música
• o dueto

That will help you remember gender more naturally.

Não funciona is the simple present and means doesn’t work. In Portuguese, the simple present is very commonly used where English might also use a progressive form.

So:

• não funciona = doesn’t work / isn’t working
• não está funcionando = is not working

Both are possible, but they can feel slightly different:

• não funciona often sounds more general or direct
• não está funcionando emphasizes the current situation right now

In this sentence, não funciona is perfectly natural.

In Portuguese, não usually goes directly before the verb it negates.

• não funciona = does not work
• não quero = I do not want
• não canto = I do not sing

So the word order is very straightforward here: o microfone não funciona = the microphone doesn’t work

The comma helps separate the two parts of the sentence:

• Quero cantar o dueto
• só que o microfone não funciona

This is similar to English punctuation before but in many sentences. It marks a pause and makes the contrast clearer.

In writing, the comma is the normal choice here.

It would be:

Eu quero cantar o dueto, só que o microfone não funciona.

This is still correct, but usually less natural unless you want emphasis on I.

You could also say:

Eu quero cantar o dueto, só que ele não funciona.

Here ele refers to o microfone, but in many cases Portuguese simply repeats the noun instead of replacing it with a pronoun.

Yes, dueto is a correct word and means duet. However, depending on context, Brazilians may also say dupla, em dupla, or use other expressions if they are talking more generally rather than naming the musical form.

Still, in a sentence about singing a specific duet, dueto is perfectly good and natural.

A rough pronunciation guide is:

KEH-roh kahn-TAR oo doo-EH-too, soh kee oo mee-kroh-FOH-nee naw foon-SYOH-nah

A few helpful notes:

• quero sounds roughly like KEH-roh
• não has a nasal sound; it is not exactly like English now
• funciona in Brazilian Portuguese often sounds like foon-syoh-nah
• só que is commonly pronounced smoothly together in speech

If spoken naturally, the rhythm would usually have a pause after dueto because of the comma.