TIL that in 1800 Alexander von Humboldt found a pet parrot in Amazonia that was the last "speaker" of an extinct language. He documented what it said, and his notes are the only trace of this language

The wording of the article does directly blame Humboldt once, and the parrot three times (if we count the headline).

if a language has not been recorded in some way, as soon as it ceases to be spoken it dies. Luckily, Humboldt had the foresight to phonetically transcribe around 40 words from the parrot’s vocabulary in his notebook, thereby successfully saving the tribe’s language from oblivion.

Parrots do have some understanding of what they're saying, so I would be willing to accept that it was the last true speaker on those grounds, but they lack much (if any) ability to teach humans those words. At the very least, I'm not aware that it taught Humboldt anything. It may have, but if so, it really should have mentioned that.

So I'm left to assume the understanding of the words are gone, and it's the understanding that's the point. The turkish word for "milk" sounds very close to the English word for "suit," but that doesn't mean you've been speaking turkish all your life. All we're left with in the case of the Atures is mimicking sounds I have no proof we've defined.

The subject of passive bilingualism is a super interesting one, though, and I've never heard of it before. It does make sense and having very little command, I could see. You do tend to understand the words of others more/faster than you can speak them yourself, but you gradually get there through repetition. By contrast, grammar is the hard part and not liable to be picked up at all without work.

But they're...including no understanding in this? One can live their life with a fluent situational understanding and not retain a single often repeated word? How? Why?? Your brain would have to squirrel away one single word, surely, even if that word is "hello" or "shut up," or "come here."