These were probably encoded in Japanese-style moras: for example, E RI ZA BE TSU, and so on. I believe I actually alternated ciphers on these, which would make it that much harder to translate.

The rest of the chart is encoded in three to four different ciphers, depending on how you count. If you count character reversals, it might be encoded in eight different ciphers. Maybe even nine.

I no longer have the original papers I used to keep track of the cipher. However, I can tell you what each of these read.

[...]

I don't particularly remember which is read left to right or right to left, or if this image is even reversed. Given that it's a cipher, it doesn't really matter. The minute you find out what a few words are, it'll be easy to figure out; but even when I was making this thing, I would often get confused.

The smaller text along the inner ring is a sentence. It is not transliterated: it is in character-for-character English, only written in the ciphertext alphabet. It's been almost a quarter of a century, and to be perfectly honest with you, I can't tell you what it says. But I remember, plain as day, all the plaintext, cleartext things that I used to generate the ciphertext: so I'll tell you those, in a minute or so.

I want to note that I purposefully did not obfuscate English particles, to make it easier to decode. You can find many of these two and three letter words in the chart: when you see them, you can safely assume they are a character-for-character English particle. 'and' and 'to' are merely guesses: it could be 'for' and 'of', or any other particles of that length. (I once toyed with making every word a random length, so that you couldn't figure it out this way. I quickly declined because it was nearly impossible to decode that way.)
[...]

Initially I believed the cipher to be too easy to decode; so I added characters not found in the English language. One character, placed after another, denotes that the previous character should be repeated. One character, used two or three times if I can remember correctly, denotes the bridging of two syllables, so it repeats the first letter of the character that comes after it. If you'd like to decode the entire thing, you need to know this.

For the rest of it, my advice is to find the vowels: I did nothing to hide them. E and A are the most-used vowels in the entire cipher, so if you do frequency analysis, you can solve this very easily. Strangely, I remember "A" being the most-frequently-used vowel, when it's usually E. Probably because there were so many names being used!

I also never used the particle 'a' by itself, instead sticking it together with the word that was after it. I did, however, allow other particles, like the words 'to', 'the', and 'and', to exist as separate words. These are easy to find in the text.

Perhaps the difficulty in translating this text is that the many English speakers who have encountered it aren't familiar with Japanese Moras. Sometimes, a ciphertext character denotes two letters: a consonant and a vowel. Other times, it denotes one character only, an English alphabet letter. This no doubt makes this a huge pain in the ass to even attempt.

My advice? Find all the different symbols. Mark them down on a piece of paper. Count them. I didn't use more than about 30.

[...]

Whenever I create something this intricate, I always lose my notes. So I always try to include what I call a "Rosetta Stone": something so obvious, so easy to detect, that it can serve as my first foothold when I come across it again and try to solve it.

For this one, if you look very carefully, you will find what should be the only instance of repeated back-to-back exact same characters in the entire chart. When you find these, you will have found the symbol for o, repeated twice. You can also find the symbol for O by figuring out which one of the three names in the spire are SHANNON. (It's going to be / should be the second-to-last letter in that name, provided I didn't spell it with a NO mora or something.)

The ciphertext, when decoded, will read ETERNAL SOLDIER SAILOR MOON. :3c