I use homemade flashcards for vocabulary. If I come across something in a text that I don't understand, I refer back to the grammar, or find a more comprehensive one that explains everything. It's a long, slow, time-intensive process, but it works for me. Speaking is different, of course.

My preferred method for learning to read (not speak) a language is to find the shortest somewhat-comprehensive grammar of the language and read it all the way through, from phonology to complex sentences. I won't remember it all but that's okay. Then I read texts with a dictionary.

I agree with this. I don't use Duolingo that much—mostly because most of the languages I want to learn aren't on it—but it seems fine to me. Duolingo won't teach you the rules of a language as such, but it can help you learn vocab and hone your intuitions. That's pretty good imo.

Today I learned that when Galileo Galilei first observed the rings of Saturn on his telescope (in 1610) he did not realise they were rings, but called them "Saturn's ears". Here's his diagram of what he could see, in a letter to Belisario Vinta:

I'm sure there'll be plenty!

Fortunately, a lot of things are Tupi-adjacent. There are Tupi words all over the place. And serendipity is fun. Be prepared but embrace chance.

I'm trying to limit my Tupi posting on here. I won't post anything until I'm prompted to by the serendipitous appearance of a Tupi-adjacent post on my timeline. I don't want to overwhelm you all with Tupi things. And I don't want to get bored myself.

(Not my fav Springsteen album but now that song's going to be in my head all day)

Sounds to me like you've worked out the trick to finding out his secret name

The Lusophone world really gets desserts right. Properly rich and gooey but with integrity and flavour. My fav is the pudim Abade de Priscos, but I can get certified gluten-free quindins at a cafe on the other side of the city so... that's where we're going later.