The evolution of nasal vowels in Portuguese out of Latin *n predates contact with Japan by centuries (see Nasal Vowel Evolution in Romance by Rodney Sampson, Oxford University Press, 1999).
It’s not unusual at all that Japanese, a language without nasal vowels, would then replace the Portuguese nasal vowel with the closest equivalent it had.
In India, the word pao or pav in street food / snacks like vada pav and pav bhaji, probably comes from the Portuguese.
https://en.m.wikipedia.org/wiki/Vada_pav
https://en.m.wikipedia.org/wiki/Pav_bhaji
My favorite variant is khada pav bhaji, in which the vegetables are in chunks, not mashed.
To support your theory, you'd need to look at a language where borrowings with nasal vowels and syllable-final nasal consonants can reliably be distingished from each other, i.e. not Japanese.
Not quite! This is a peculiarity of Japanese transcription: the moraic nasal [0] is often transcribed as /ɴ/ or /N/ in phonemic representation, while its phonetic realisation varies between [m~n~ɲ~ŋ]; it is true uvular [ɴ] only utterance-finally, but apparently even that is controversial.
[0] https://en.wikipedia.org/wiki/Japanese_phonology#Moraic_nasa...
(Maybe I’m just too used to people getting confused about this stuff…)
(They did have steamed grain products, just not baked ones.)
Don't know about balconies.
There are also many cracker-like hard "breads" made from rice flour, notably sensei, but these too are snacks, not mains.
I don't suggest eating balconies.
You can make cakes with rice though, which they did have.
(When you see modern gluten-free bread in a bakery/supermarket, it’s still basically a cake recipe, tweaked to resemble the texture of bread)
As for why they use a loan word for "door", I'm guessing it's due to the wide adoption of Western-style doors for which there's no equivalent word in Japanese. And why loaned from English instead of any other language, like Portuguese? I imagine it has some historical reason, related to which country such doors were originally imported from.
The introduction through trade also applies to other eastern countries - China was exposed through the silk road, India through Portuguese and middle eastern trade.
You have similarly surprising culinary events in the West. Tomatoes weren't introduced to Italy until the 16th century, an tomato sauce wasn't a thing before the 18th century - before that, pasta (itself assumed to come from Chinese noodles) was eaten dry with your fingers. Potatoes first arrived in Europe around the same time.
I ask myself that every day. I think the answer is prestige.
In my language, Romanian, many words are borrowed from English because there's no home-grown equivalent, like "hacker".
But even common words are being replaced with English ones. E.g. fashion instead of modă, know-how instead of cunoștințe (knowledge), brand — marcă, however – însă (you know your language is in danger of disappearing when the conjunctions are being replaced).
This is in spite of the fact that people can often hardly pronounce the English words, for example businessman is pronounced /biznismen/ (with no way to differentiate between man and men), or pronouncing "guard" as "goo-ard".
If age-related reversion to the old way of speaking was a universal given then we wouldn't see half the linguistic drift that we do.
You also hear experts use English terms because it makes them look more sophisticated. For example instead of saying the equivalent of "Ukrainians need to be trained to use American weapons" with all-Romanian words, you'll hear "Ukrainians need KNOW-HOW to use American weapons" with "know-how" being untranslated, even though this sentence is more awkward than the first one.
I don't know the evolution of the terms in question, but I wouldn't be surprised if they didn't!
Like, what is a beach (or пляж)? It's basically берег (riverbank/seashore) but intended for recreation use. Did people of the past have enough time to recreationally use their seashores/riverbanks? I wouldn't be surprised if they didn't.
Same about furniture/мебель. I would assume that in the past (at least in the villages), people would often have benches, beds, tables custom-made specifically for their house, and they would not be meant to be moved out.
Мебель/furniture presupposes that people produce it in one place, and then people move it to their house, and this was often not the case in the past.
If your bed is made when your house is built, and cannot be moved out because bed frame goes directly into your wall, is that still furniture? Is furniture a useful word to describe that?
(Not sure about screens)
That's because Japanese is extremely phonetically poor.