Learn Hardcore Portuguese (Portugal): A professora diz que cada aluno é responsável pelo seu próprio estudo. - The teacher says that each student is responsible for their own studying.

A professora = the teacher (female). The definite article a is normally used before professions when you’re talking about a specific person (a specific teacher).
Portuguese does not normally use a subject pronoun plus a full noun the way English sometimes does (e.g. A professora ela diz…). You just say A professora diz….

So:

A professora diz… = The (female) teacher says…
You would only say Professora, diz… if you’re directly addressing her (like “Teacher, say…”), and then Professora works more like a form of address, not the subject of the sentence.

Why is professora feminine but aluno masculine? Isn’t the teacher talking about both male and female students?

Professora is feminine because we are clearly talking about a female teacher.
Aluno is grammatically masculine, but in Portuguese the masculine singular can be used in a generic way for “each student” (male or female).

Alternatives:

cada aluno – grammatically masculine, but can be understood as “each student (in general)”.
cada aluna – “each (female) student”, only females.
cada aluno e cada aluna – explicitly mentions both genders, but sounds heavier.
cada estudante – gender‑neutral in form, often used in more formal or inclusive language.

The original sentence uses the common pattern: female teacher, generic masculine for students.

What does diz que mean here, and could I leave out que like in English “The teacher says each student is responsible…”?

diz = “says” (3rd person singular of dizer, “to say”).
que here is the conjunction “that”.

So diz que = “says that”.

In English, “that” is often optional:

The teacher says (that) each student is responsible…

In Portuguese, the que is not optional in this structure. You must keep it:

✅ A professora diz que cada aluno é responsável…
❌ A professora diz cada aluno é responsável… (incorrect)

So que introduces the reported clause cada aluno é responsável pelo seu próprio estudo.

Why is it cada aluno é (singular) and not something like cada aluno são (plural) or cada alunos são?

Cada (“each”) is always singular in Portuguese, just like in English:

cada aluno é = “each student is”
never cada alunos são

If you want a plural idea (“all the students”), you don’t use cada, you use something like:

todos os alunos são responsáveis… = “all (the) students are responsible…”

Why is responsável the same form for aluno and aluna? Doesn’t the adjective change with gender?

Many adjectives in Portuguese do change with gender (e.g. aluno aplicado / aluna aplicada).

But adjectives ending in -vel (like responsável) are usually:

the same form for masculine and feminine
they only change for number (singular/plural)

So:

o aluno é responsável
a aluna é responsável
os alunos são responsáveis
as alunas são responsáveis

Only the plural adds -s: responsáveis.

Why is it responsável por and not responsável de or responsável para?

In Portuguese, adjectives and verbs often have fixed prepositions that just have to be memorized.

For responsável, the usual pattern is:

responsável por
- noun or gerund

Examples:

responsável pelo projeto – responsible for the project
responsável por organizar a reunião – responsible for organizing the meeting

So in this sentence we say:

responsável pelo seu próprio estudo
not
❌ responsável de
❌ responsável para

Even if in English we say “responsible for”, you must know/remember that in Portuguese it’s responsável por.

What exactly is pelo here? How is it formed?

Pelo is a contraction of the preposition por and the masculine singular definite article o:

por + o = pelo

So:

por o estudo → pelo estudo = “for the study”

Other common contractions:

por + a = pela (pela casa – for the house)
por + os = pelos
por + as = pelas

In this sentence:

responsável por + o estudo → responsável pelo estudo

What does seu mean here? Could it be “his”, “her”, “their”, or even “your”?

Yes, seu is context‑dependent and can be ambiguous on its own. It can mean:

his
her
its
your (formal singular or plural)
their

In this sentence:

cada aluno é responsável pelo seu próprio estudo

The most natural reading is:

seu = “his/her own”, referring back to cada aluno.

Because cada aluno is singular and generic, seu is understood as “each student’s own”.

In other contexts, seu can be ambiguous, so speakers sometimes avoid it and say dele / dela / deles / delas to be clearer:

o estudo dele – his study
o estudo dela – her study

But here the context makes seu clear.

If seu already means “his/her own”, why do we also have próprio? Isn’t seu próprio redundant?

Literally:

seu estudo = “his/her study” (or “their study”, etc.)
seu próprio estudo = “his/her own study”

The word próprio adds emphasis on “own”, just like in English:

“Each student is responsible for his/her study.”
“Each student is responsible for his/her own study.” (stronger emphasis on personal responsibility)

So seu próprio isn’t grammatically necessary, but it reinforces the idea that the responsibility is personal, not shared.

Why is it estudo (singular) and not estudos (plural)?

In Portuguese, estudo can be:

a countable noun – “a study” (a piece of research), or “studies” in the academic‑subject sense
an uncountable / abstract noun – “study” as an activity or process.

Here it’s uncountable and abstract:

o seu próprio estudo ≈ “your own studying / your own study habits / your own learning”

You could say os seus próprios estudos, but:

o seu próprio estudo sounds more like the overall activity / responsibility of studying
os seus próprios estudos can put more focus on specific courses or pieces of work

Both are possible, but the singular abstract estudo is very natural here.

Could this sentence also be used in Brazil, or is it specifically European Portuguese?

The sentence:

A professora diz que cada aluno é responsável pelo seu próprio estudo.

is perfectly natural in both European and Brazilian Portuguese.

Small notes:

In speech, Brazilian Portuguese might be more likely (not obligatory) to drop the article with a proper name:
- A professora Ana diz… (PT/BR) vs sometimes Professora Ana diz… (BR), but here we don’t have a name, just a professora, so it’s the same.
Pronunciation will differ, but the grammar and wording are fully acceptable in both varieties.

How is responsável pronounced, and what does the accent mark do?

Responsável is pronounced roughly:

European Portuguese: [ʁɨʃ-põ-za-vɛl] (with the typical EP vowel reduction and nasal -spon-)
Brazilian Portuguese: [ʁes-põ-za-vew]

The accent mark ´ on responsável shows:

Where the stress is: on -sá- → res‑pon‑sá‑vel
That the vowel is open á (not the closed â sound).

Without the accent it would be an incorrect spelling (responsavel is wrong); the accent is part of the correct written form and guides stress and vowel quality.