O professor cujos alunos falam pouco português vai explicar a lição de novo.

Cujos means whose.

In this sentence, O professor cujos alunos falam pouco português... means The teacher whose students speak little Portuguese...

A key point: cujo / cuja / cujos / cujas shows possession and connects two nouns:

• o professor
• os alunos do professor

So instead of saying something like o professor, os alunos dele..., Portuguese can use cujo to make it more compact and formal.

Because cujo agrees with the thing that comes after it, not with the owner.

Here, the possessed thing is alunos, which is:

• masculine
• plural

So the correct form is cujos.

The forms are:

• cujo = masculine singular
• cuja = feminine singular
• cujos = masculine plural
• cujas = feminine plural

Examples:

• o professor cujo aluno chegou = the teacher whose student arrived
• o professor cujos alunos chegaram = the teacher whose students arrived
• a professora cuja filha mora aqui = the teacher whose daughter lives here
• a professora cujas filhas moram aqui = the teacher whose daughters live here

Not exactly.

It is often translated as whose, but Portuguese uses cujo more formally and with stricter grammar.

Important difference: you do not normally use an article after cujo.

So:

• correct: o professor cujos alunos falam pouco português
• not standard: o professor cujos os alunos...

That is different from English, where whose the students is impossible anyway, but learners often want to insert os because alunos usually takes an article in Portuguese.

Not with that exact structure, and in general cujo is the more correct way to express this idea.

If you want a more conversational alternative, Brazilian Portuguese often avoids cujo in speech and uses other structures, such as:

• o professor cujos alunos falam pouco português (more formal / standard)
• o professor de quem os alunos falam pouco português (this changes the meaning, so it is not right here)
• o professor que tem alunos que falam pouco português (different structure, more natural in speech)

A very common spoken workaround is to restructure the sentence:

• O professor tem alunos que falam pouco português. Ele vai explicar a lição de novo.

So yes, Brazilians often avoid cujo in everyday speech, but in careful written Portuguese, cujo is perfectly good and elegant.

Because the subject of the verb is alunos, which is plural.

In the clause cujos alunos falam pouco português:

• subject = alunos
• verb = falam

So the verb must be plural:

• o aluno fala
• os alunos falam

Even though the whole sentence starts with O professor, the verb falam belongs to alunos, not to professor.

It means little Portuguese or not much Portuguese.

Here, pouco is functioning like an indefinite quantity:

• falar pouco português = to speak little Portuguese

This is very common in Portuguese:

• falo muito inglês
• ela fala pouco espanhol
• eles entendem bastante francês

So pouco is not describing português as an adjective in the sense of small Portuguese. It is expressing quantity: the students speak only a small amount of Portuguese.

Because after verbs like falar, languages often appear without an article in Portuguese.

So you commonly say:

• falo português
• ela fala inglês
• nós estudamos espanhol

That is similar to English, which also says speak Portuguese, not speak the Portuguese.

You may sometimes see an article in special contexts, but in a basic sentence like this, no article is the normal choice.

Vai explicar is the periphrastic future, built with ir + infinitive. It is extremely common in Brazilian Portuguese.

So:

• vai explicar = is going to explain / will explain

Other possibilities:

• explicará = simple future, more formal or written
• explica = present tense; depending on context, it can refer to a scheduled future, but that is not the main reading here

In everyday Brazilian Portuguese, vai explicar often sounds more natural than explicará.

Both can mean again, but de novo is usually more common and natural in everyday Brazilian Portuguese.

So:

• vai explicar a lição de novo = will explain the lesson again
• vai explicar a lição novamente = will explain the lesson again

Novamente can sound a bit more formal or emphatic depending on context.
In normal conversation, de novo is often preferred.

Portuguese uses articles more often than English.

Here, a lição means the lesson. It refers to a specific lesson that speaker and listener can identify from context.

Portuguese very often includes the definite article where English also uses the, and sometimes even where English would omit it.

So:

• explicar a lição = explain the lesson
• estudar a matéria = study the material
• abrir o livro = open the book

The sentence is built like this:

• O professor = the teacher
• cujos alunos falam pouco português = whose students speak little Portuguese
• vai explicar a lição de novo = is going to explain the lesson again

So the main subject is:

• O professor

The relative clause in the middle gives extra information about that professor:

• cujos alunos falam pouco português

Then the main verb phrase is:

• vai explicar a lição de novo

A simple way to see it is:

[The teacher] [whose students speak little Portuguese] [is going to explain the lesson again].

It is correct and important to know, but in everyday speech it can sound somewhat formal.

In writing, news, literature, academic Portuguese, and careful formal speech, cujo is quite normal.

In casual conversation, many speakers prefer to avoid it by rephrasing:

• O professor tem alunos que falam pouco português.
• Os alunos do professor falam pouco português, então ele vai explicar a lição de novo.

So as a learner:

• you should definitely recognize and understand cujo
• it is useful to use in writing
• in casual speech, rephrasing is often more natural

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

So:

• português
• inglês
• espanhol
• brasileiro

This is different from English, where you write Portuguese, English, Spanish, etc. with capital letters.

Not always. They are related, but they do not mean exactly the same thing.

• lição usually means lesson, exercise, or the material being taught
• aula usually means class or lesson period

So:

• explicar a lição de novo = explain the lesson again
• dar a aula de novo = teach the class again

If the idea is that the teacher will explain the content again, lição works well.
If the idea is repeating the class session itself, aula might be better.

Yes. English speakers often try to build it too literally.

A common mistake is using something like:

• o professor que seus alunos...
• o professor que os alunos dele...

These may sound clumsy or incorrect when you specifically want a neat whose relationship.

The standard written solution is:

• o professor cujos alunos...

So when you see whose + noun in English, it is worth checking whether cujo / cuja / cujos / cujas is the best Portuguese option.