Of course, there's the C Major thing :)
And I didn't know about Movable Solfège, thanks! I'll have to study that.
But, to put it in audio perspective rather than comparing words and letters, why is the note that corresponds to 440 Hz named A and not F -- implying that, going lower and lower from 440 Hz for each note, 261.63 Hz would not be named C but rather A instead.
Or, to use maybe a comparison that would work from whence those two notation systems were created/named (I figure with a keyboard nearby), why is the first note of a standard piano octave (you know, this: [1]) labelled C and not A? Since it's the first note of the octave and since the German system is using the alphabet (which, well, starts with A), wouldn't it have made sense to have that first octave piano key be labelled A too :)
[1] https://www.hellosimply.com/blog/wp-content/uploads/2022/03/...
I've seen this conversation several times online, and it's funny to see how participants cannot agree on what is being talked about here, and no conclusion is reached. So I'm aware that I might be asking a super dumb beginner question, but I really do wonder why Do=C and not Do=A.
Don't hesitate to slap me with a "origins of musical notation systems" link, I love to read about music and history :)