A motorista do táxi não parava de tocar a buzina, porque ninguém avançava no cruzamento.

Because motorista is a common-gender noun in Portuguese. The noun itself stays the same for a male or female driver, and the article shows the gender:

• o motorista = the male driver
• a motorista = the female driver

So a motorista do táxi means the female taxi driver.

Because in Portuguese, de + o normally contracts to do.

So:

• de o táxi → do táxi

This is very common:

• de + a → da
• de + os → dos
• de + as → das

Here, a motorista do táxi literally means the driver of the taxi, though in natural English we usually say the taxi driver.

Não parar de + infinitive means to not stop doing something or to keep doing something.

So:

• não parava de tocar a buzina = she wouldn’t stop honking / she kept honking

It is a very common structure in Portuguese:

• Ele não parava de falar. = He wouldn’t stop talking.
• Ela não parava de rir. = She couldn’t stop laughing.

Parava is the imperfect tense. It suggests an ongoing, repeated, or background action in the past.

Here it gives the idea that the driver was continuously or repeatedly honking over a period of time.

Compare:

• não parava de tocar a buzina = she kept honking / she wouldn’t stop honking
• não parou de tocar a buzina = she did not stop honking (more like a completed past event, seen as a whole)

The imperfect fits well because the sentence describes a situation in progress.

Yes, tocar often means to touch or to play, but in this expression tocar a buzina means to sound the horn or simply to honk.

It is an idiomatic everyday expression. In European Portuguese, buzina is the vehicle horn, and tocar a buzina is the normal way to say to honk.

So although the literal wording may feel unusual to an English speaker, the natural meaning is just to honk the horn.

Portuguese often uses the definite article where English might leave it out.

So:

• tocar a buzina literally = to sound the horn
• natural English = to honk

Using the article here is normal Portuguese. You will often see this with body parts, objects, and common actions:

• lavar as mãos = to wash your hands
• fechar os olhos = to close your eyes
• tocar a buzina = to honk the horn

Because ninguém means nobody / no one, and grammatically it takes a singular verb in Portuguese.

So:

• ninguém avançava = nobody was moving forward

Even though ninguém refers to multiple people in meaning, it behaves like a singular subject.

The same happens in English:

• Nobody was moving, not Nobody were moving

Here avançava means was moving forward, went forward, or pulled ahead.

In traffic contexts, avançar often means to move ahead when there is space or when the light changes.

So porque ninguém avançava no cruzamento means something like:

• because nobody was moving forward at the intersection
• because no one was proceeding through the junction

Again, the imperfect avançava shows an ongoing situation in the past.

Because em + o contracts to no.

So:

• em o cruzamento → no cruzamento

This is another very common contraction:

• em + a → na
• em + os → nos
• em + as → nas

So no cruzamento means in the intersection or at the intersection, depending on the context.

Both can relate to an intersection, but cruzamento is the more common everyday word for a road junction or crossroads.

• cruzamento = usual everyday word
• interseção = more formal, technical, or mathematical in many contexts

So in normal traffic language, no cruzamento sounds very natural.

Because here it means because, introducing the reason.

Portuguese has several similar-looking forms:

• porque = because
• porquê = the reason / the why
• por que = why / for which
• por quê = why, usually at the end of a question

In your sentence, it gives the cause:

• porque ninguém avançava no cruzamento = because nobody was moving forward at the intersection

Yes, that is a very natural translation.

A few good English versions are:

• The taxi driver kept honking because nobody was moving forward at the intersection.
• The taxi driver wouldn’t stop honking because no one was moving at the junction.
• The female taxi driver kept sounding the horn because nobody was advancing through the intersection.

The most natural choice in everyday English is probably kept honking.

Yes, a couple of things feel very natural in European Portuguese:

• tocar a buzina is a very normal way to say to honk
• cruzamento is the standard everyday word for intersection/junction
• the use of articles, as in a motorista and a buzina, is also very typical of natural Portuguese structure

A Brazilian Portuguese speaker would understand the sentence perfectly, but some wording choices or rhythm might vary slightly depending on region.