But I guess the system only began to approach the combinatorial complexity that makes it worthy of the word "system" once I started adding the diacritics. I think ~ was the first one. As I recall, I probably decided to create a character for -ant—or maybe -ent. That's the thing—why make a whole letter for -ent, -ant, etc., when you can generalize to -Vnt?
I figured the tilde would be an appropriate character for it; already in the IPA and Portugese et al it nasalizes the vowel that you write it over. So now ã means ant and ẽ means ent and so on.