Bip39 hash https://collinmmss433.lucialpiazzale.com/from-concept-to-fact-generating-bitcoin-addresses-with-bip39 BIP85: A more moderen proposal letting the deterministic derivation of several BIP39 mnemonic seeds from the learn seed. For words that only have 3 letters, there isn't any 4th letter. As an example with the word “incorporate”, there won't be any additional letters Later on... https://bookmarkleader.com/story20854223/bip39-how-many-combinations-not-known-factual-statements-about-bip39-mnemonic-https-t-me-bip39-chat