Bip39 hardware https://blogfreely.net/travenmdoq/create-your-own-distinct-bip39-mnemonic-expression-with-python-scripts BIP85: A more moderen proposal allowing for the deterministic derivation of a number of BIP39 mnemonic seeds from the master seed. For words that only have three letters, there isn't a 4th letter. One example is Using the word “add”, there aren't any additional lette... https://bookmarklethq.com/story20322105/bip39-format-example-helping-the-others-realize-the-advantages-of-bip39-recovery-tool-https-cutt-ly-uryc5rw7