Bip39 library https://www.anobii.com/en/01000289012ff9b293/profile/activity BIP85: A more recent proposal allowing the deterministic derivation of various BIP39 mnemonic seeds from a master seed. For words that only have 3 letters, there is absolutely no 4th letter. One example is Using the word “include”, there aren't any a lot more letters afterwards and https://bookmarkalexa.com/story6017472/bip39-hardware-new-step-by-step-map-for-bip39-github-https-dzen-ru-bip39-phrase-com