Learn Hardcore Portuguese (Portugal): De manhã, eu sinto alergia quando abro a janela do quarto. - In the morning, I feel allergy symptoms when I open the bedroom window.

You don’t usually say “na manhã” unless you mean a specific morning (e.g. na manhã de terça-feira = on Tuesday morning), and “à manhã” is simply not used in Portugal for this meaning. Here “De manhã” means “in the morning (generally / habitually)”.

Is the comma after “De manhã,” necessary?

It’s not strictly mandatory, but it’s very common and stylistically natural.
“De manhã” is an introductory time expression; putting a comma after it helps mark a pause and makes the sentence easier to read:

De manhã, eu sinto alergia…
Eu sinto alergia de manhã quando abro a janela do quarto. (no comma needed here)

Both are correct; it’s mainly a question of style and rhythm.

Could I drop “eu” and just say “De manhã, sinto alergia…”?

Yes. In European Portuguese, subject pronouns (eu, tu, ele, etc.) are often omitted because the verb ending already shows who the subject is.

De manhã, sinto alergia… – perfectly natural
De manhã, eu sinto alergia… – also correct; using “eu” can slightly emphasize “I”.

So omitting “eu” is very common and not informal or wrong.

Why is it “sinto alergia” (literally “I feel allergy”)? Wouldn’t “tenho alergia” or “sou alérgico” be more natural?

All three are possible, but they feel slightly different:

Eu tenho alergia quando abro a janela… – “I have an allergy when I open the window…” (neutral, common)
Eu sou alérgico ao pó / ao pólen… – “I’m allergic to dust / pollen…” (describes a permanent condition)
Eu sinto alergia quando abro a janela… – “I feel allergy symptoms when I open the window…”

“Sinto alergia” sounds like “I feel allergy coming on / I feel allergy symptoms”. In everyday speech in Portugal, “tenho alergia” or “fico com alergia” might be more natural, but “sinto alergia” is grammatically correct.

Why is it “sinto alergia” and not “sinto-me com alergia”?

Sentir-se is reflexive when you mean “to feel (oneself) in a certain state”:

Sinto-me mal. – I feel bad.
Sinto-me doente. – I feel ill.

With alergia, you can use either pattern, but they’re slightly different:

Sinto alergia. – I feel allergy (symptoms).
Sinto-me com alergia. – I feel like I have an allergy / I feel allergic right now.

The original sentence focuses on the symptoms appearing, so “sinto alergia” works. Using “sinto-me com alergia” would sound more like “I feel I’m in an allergic state.”

Why is “quando abro” in the present tense, and not something like “quando abrir”?

Portuguese uses the present indicative for actions that are habitual or generally true, just like English:

Quando abro a janela, sinto alergia. – Every time I open the window, I get allergy symptoms.

“Quando abrir” would normally appear in a future context:

Quando abrir a janela, vais sentir alergia. – When you open the window (in the future), you will feel allergy.

Here we’re talking about a repeated pattern, so present indicative (abro, sinto) is the natural choice.

Can I say “quando eu abro” instead of “quando abro”?

Yes. Both are correct:

Quando abro a janela, sinto alergia.
Quando eu abro a janela, sinto alergia.

Dropping “eu” is very common; the verb ending -o already shows the subject is “I”. Adding “eu” can add a slight emphasis on I (as opposed to someone else).

Could I say “Ao abrir a janela do quarto, eu sinto alergia” instead of “quando abro a janela do quarto”?

Yes, that’s a good alternative:

Ao abrir a janela do quarto, eu sinto alergia. – On opening / When I open the bedroom window, I get allergy symptoms.

“Ao + infinitivo” often expresses “when/whenever doing something”. It sounds slightly more formal or literary than “quando abro”, but it’s perfectly correct and natural in European Portuguese.

What exactly is “do” in “a janela do quarto”?

“Do” is a contraction of “de + o”:

de – of / from
o – the (masculine singular)

So “do quarto” literally means “of the bedroom”.

A janela do quarto = the window of the bedroom → the bedroom window. Contractions like do, da, dos, das are very common and almost always preferred over saying de o, de a, de os, de as.

Why is it “a janela do quarto” and not “a janela do meu quarto”? How do we know it’s my bedroom?

Context usually supplies the possessive. If you’re talking about your own routine:

De manhã, eu sinto alergia quando abro a janela do quarto.

listeners will naturally understand “my bedroom”. Portuguese often omits possessive adjectives where English would require them, especially with body parts, clothes, and things closely associated with the subject:

Lavei as mãos. – I washed my hands.
Fechei a porta do carro. – I closed my (own) car door.

If you really want to emphasize it’s your bedroom, you can say:
“…quando abro a janela do meu quarto.”

Does “quarto” always mean “bedroom”? I thought it could just mean “room”.

In modern European Portuguese, “quarto” by itself most commonly means “bedroom”.
“Room” in general is “sala” or “divisão” (more formal/technical):

quarto – bedroom
sala – living room / lounge
quarto de hotel – hotel room (often just quarto in context)

In “a janela do quarto”, the default reading is “the bedroom window”.

Can I change the word order, like “Eu sinto alergia de manhã quando abro a janela do quarto”?

Yes. That sentence is completely natural and maybe even more common in spontaneous speech:

Eu sinto alergia de manhã quando abro a janela do quarto.

You can also say:

De manhã, eu sinto alergia quando abro a janela do quarto.
Eu, de manhã, sinto alergia quando abro a janela do quarto. (with extra emphasis on in the morning)

Portuguese word order is fairly flexible; moving “de manhã” mainly changes emphasis and rhythm, not meaning.

Is “alergia” countable in Portuguese? Could I say “tenho alergias”?

Usually “alergia” is treated as an uncountable condition in everyday speech:

Tenho alergia ao pó. – I’m allergic to dust.
Tenho muita alergia na primavera. – I get bad allergies in spring.

You can say “tenho várias alergias” (I have several allergies) if you’re talking about different types, e.g. dust, pollen, certain foods. In the original sentence, “alergia” is being used as a general condition, so the singular is normal.

How should I pronounce “manhã” and “janela” in European Portuguese?

Very roughly (not IPA):

manhã – muhn-YAHN
- The “ã” is a nasal vowel; you don’t fully pronounce a final “n”, you just nasalize the vowel.
janela – zhuh-NEL-uh
- Initial “j” is like the “s” in English “measure”.
- Final “a” in unstressed position is a very short, almost “uh” sound in Portugal.

So the sentence flows something like:
[də muhn-YAHN], [eu SEEN-tu uh-leh-RZEE-uh] [kwan-duh A-broo a zhuh-NEL-uh du KWAR-tu].
(That’s a rough guide to get you close to European Portuguese pronunciation.)