Bip39 spec https://www.storeboard.com/myrtierisaliti The last phase of BIP-39 is producing the actual binary seed which happens to be then applied to be a master key in BIP-32 deterministic wallet or working with other methods. For words that only have 3 letters, there is not any 4th letter. Such as With https://rylanmecp341.wpsuo.com/bip32-vs-bip39-which-is-better-for-your-copyright-demands