Bip39 vs bip84 https://www.cheaperseeker.com/u/adeneuwaks BIP85: A more moderen proposal allowing the deterministic derivation of a number of BIP39 mnemonic seeds from a learn seed. For words that have only three letters, there isn't any 4th letter. One example is Using the word “insert”, there are no more letters Later on https://thegreatbookmark.com/story20467854/bip39-ledger-examine-this-report-on-bip39-vs-slip39-https-linktr-ee-bip39