This looks awesome! For written Portuguese, how different is Brazillian vs European? I've been trying to learn European Portuguese and it is challenging to find resources that differentiate between the two.
(1) European Portuguese usually fully preserves "tu" (including distinctive verb forms), while in Brazilian Portuguese, it's often only used in oblique forms "te" and "ti", or regionally as a subject but often with the third person verb form. For example, in much of Brazil you would see "você tem" (even when speaking to a close friend or family member); in some parts of Brazil, like in Rio Grande do Sul, you would see "tu tem"; and in Portugal you might see "tu tens".
(2) European Portuguese uses "a" + infinitive where Brazilian Portuguese uses the present participle: "estou a fazer" versus "estou fazendo", or "está a falar" versus "está falando". This distinction is very strong and consistent.
(3) Pronunciation can be very different. The first thing you would notice is that the <d> before <e> and <i> is not pronounced as /dʒ/ and the <t> before those letters is not pronounced as /tʃ/. So for example <diabo> 'devil' or <diagonal> 'diagonal' start with /dʒ/ in Brazil but with /d/ in Europe, or <sede> 'thirst' ends with /dʒi/ in Brazil but /dɨ/ in Europe. Or especially the adjective ending <-mente> will be /'mẽtʃi/ in Brazil but /'mẽtɨ/ in Europe.
The word-final vowels in European Portuguese often seem to get dropped entirely (or to be pronounced very softly or briefly), so you might even hear that adverb ending as /mẽt/ (approaching French!!).
I found it fairly challenging as a non-native speaker.
All your points are correct! Awesome observation!
I'm from south Brazil, living in Rio, and I have some weird situations following people from the north when they talk fast. I need to spend more energy paying attention or ask again the same question, but it's a nice exercise.
It's closely related to the immigrations, for instance the city I lived in the south had a bigger immigration from Azorians, along with different proportions of europeans on the entire state, including my (grand)grandparents from Poland.
When I started looking at the cultural origins it made more sense, it's also a beautiful topic to look at.