https://www.oreilly.com/library/view/mastering-bitcoin-2nd/9781491954379/ch04.html
Discussion
What’s the upshot in relation to my suggestion?
I don’t know much bitcoin, but it appears that you need a mathematically rigorous algorithm with similar entropy to produce your phrase (so you can’t just pick words that might mean something to you, from the Electrum page) but that “easier to remember” is being worked on in the wallet space. If you care to it appears you can dig in pretty deep in how it works.
Yes, it has to be 256 bits, or 64 hexadecimals or 24 words out of something like 4,096. But is there some fundamental reason you couldn’t expand the words to include the entire English language (you can do this with passphrases already)? In which case, my idea would be to create sufficient entropy out of personal items/facts someone already knows.
I thought maybe there were math reasons (that I don’t understand) but it might just be: “It is not safe to invent your own seed phrase because humans are bad at generating randomness. The best way is to allow the wallet software to generate a phrase which you write down.” https://en.bitcoin.it/wiki/Seed_phrase